diff --git a/sync/model_manager.py b/sync/model_manager.py
new file mode 100644
index 0000000..e69de29
diff --git a/sync/models/base.py b/sync/models/base.py
index 8668e9d..dc123a7 100644
--- a/sync/models/base.py
+++ b/sync/models/base.py
@@ -1,9 +1,14 @@
 from django.db import models
 from django.utils.timezone import now
 from django.conf import settings
+from django.apps import apps
+
 from typing import List, Set
 
-from django.apps import apps
+from collections import defaultdict
+import logging
+
+logger = logging.getLogger(__name__)
 
 class BaseModel(models.Model):
     creation_date = models.DateTimeField(default=now, editable=False)
@@ -28,22 +33,22 @@ class BaseModel(models.Model):
         else:
             return None
 
+    def data_identifier_dict(self):
+        return {
+            'model_id': self.id,
+            'store_id': None
+        }
+
     def update_data_access_list(self):
-        related_instances = self.related_instances()
-        related_ids = [ri.id for ri in related_instances]
-        related_ids.append(self.id)
-
-        DataAccess = apps.get_model('sync', 'DataAccess')
-        data_accesses = DataAccess.objects.filter(model_id__in=related_ids)
-        for data_access in data_accesses:
-            self.add_data_access_relation(data_access)
-
-        # add data_access to children who might not had the relationship
-        # if data_accesses:
-        #     for child in self.get_children_by_model():
-        #         if len(child.data_access_ids) == 0:
-        #             for data_access in data_accesses:
-        #                 self.add_data_access_relation(data_access)
+        related_instances = self.sharing_related_instances()
+        data_access_ids = {instance.data_access_ids for instance in related_instances}
+        data_access_ids.update(self.data_access_ids)
+        self.data_access_ids = data_access_ids
+
+        # DataAccess = apps.get_model('sync', 'DataAccess')
+        # data_accesses = DataAccess.objects.filter(model_id__in=related_ids)
+        # for data_access in data_accesses:
+        #     self.add_data_access_relation(data_access)
 
     def add_data_access_relation(self, data_access):
         str_id = str(data_access.id)
@@ -187,8 +192,60 @@ class BaseModel(models.Model):
 
         return None
 
+    def sharing_related_instances(self):
+        """
+        Get all related instances (both children and parents) recursively
+        """
+        instances = []
+        processed_objects = set()
+        instances.extend(self.get_shared_children(processed_objects))
+
+        processed_objects = set()
+        instances.extend(self.get_recursive_parents(processed_objects))
+
+        return instances
+
+    def get_shared_children(self, processed_objects):
+
+        sync_models = getattr(settings, 'SYNC_MODEL_CHILDREN_SHARING', {})
+        relationships = sync_models[self.__class__.__name__]
+        if relationships:
+            return self.get_shared_children_from_relationships(relationships, processed_objects)
+        else:
+            return self.get_recursive_children(processed_objects)
+
+    def get_shared_children_from_relationships(self, relationships, processed_objects):
+
+        # print(f'relationships = {relationships}')
+        current = [self]
+        for relationship in relationships:
+            # print(f'> relationship = {relationship}')
+            values = []
+            for item in current:
+                value = getattr(item, relationship)
+
+                if hasattr(value, 'all') and callable(value.all):
+                    # This is a queryset from a reverse relationship
+                    for related_obj in value.all():
+                        processed_objects.add(related_obj)
+                    values.extend(value.all())
+                else:
+                    processed_objects.add(value)
+
+                    values.append(value)
+            current = values
+
+        logger.info(f'+++ shared children = {processed_objects}')
+        return processed_objects
+
 class SideStoreModel(BaseModel):
     store_id = models.CharField(max_length=100, default="") # a value matching LeStorage directory sub-stores. Matches the name of the directory.
 
     class Meta:
         abstract = True
+
+    def data_identifier_dict(self):
+        return {
+            'model_id': self.id,
+            'store_id': self.store_id
+        }
diff --git a/sync/models/data_access.py b/sync/models/data_access.py
index a371eb7..1e41874 100644
--- a/sync/models/data_access.py
+++ b/sync/models/data_access.py
@@ -69,7 +69,8 @@ class DataAccess(BaseModel):
         if model_class:
             try:
                 obj = model_class.objects.get(id=self.model_id)
-                related_instance = obj.related_instances()
+
+                related_instance = obj.sharing_related_instances()
                 related_instance.append(obj)
 
                 with transaction.atomic():
diff --git a/sync/registry.py b/sync/registry.py
index f27b2e2..1f42797 100644
--- a/sync/registry.py
+++ b/sync/registry.py
@@ -1,8 +1,16 @@
 from django.conf import settings
 from django.apps import apps
-from .models import BaseModel
 from django.contrib.auth import get_user_model
+
+from .models import BaseModel
+
 import threading
+import logging
+
+from typing import List, Optional, Dict
+
+
+logger = logging.getLogger(__name__)
 
 User = get_user_model()
 
@@ -105,3 +113,173 @@ class RelatedUsersRegistry:
 
 # Global instance
 related_users_registry = RelatedUsersRegistry()
+
+
+class SyncModelChildrenManager:
+    """
+    Manager class for handling model children sharing configuration.
+    Reads the SYNC_MODEL_CHILDREN_SHARING setting once and builds a bidirectional
+    relationship graph for efficient lookup.
+    """
+
+    def __init__(self):
+        """Initialize the manager by reading the Django setting and building the relationship graph."""
+        self._model_relationships = getattr(
+            settings,
+            'SYNC_MODEL_CHILDREN_SHARING',
+            {}
+        )
+        self._relationship_graph = self._build_relationship_graph()
+        logger.info(f'self._relationship_graph = {self._relationship_graph}')
+
+    def _build_relationship_graph(self) -> Dict[str, List[List[str]]]:
+        """
+        Build a bidirectional relationship graph.
+
+        Returns:
+            Dict[str, List[List[str]]]: Dictionary where keys are model names and values
+            are lists of relationship paths (arrays of relationship names).
+        """
+        graph = {}
+
+        # Add direct relationships (original models to their children)
+        for model_name, relationships in self._model_relationships.items():
+            if model_name not in graph:
+                graph[model_name] = []
+
+            # Add direct relationships as single-item arrays
+            for relationship in relationships:
+                graph[model_name].append([relationship])
+
+        # Build reverse relationships (children back to original models)
+        for original_model_name, relationships in self._model_relationships.items():
+            try:
+                original_model = model_registry.get_model(original_model_name)
+                if original_model is None:
+                    continue
+
+                for relationship_name in relationships:
+                    # Get the related model through _meta
+                    try:
+                        field = None
+                        # Try to find the field in the model's _meta
+                        for f in original_model._meta.get_fields():
+                            if hasattr(f, 'related_name') and f.related_name == relationship_name:
+                                field = f
+                                break
+                            elif hasattr(f, 'name') and f.name == relationship_name:
+                                field = f
+                                break
+
+                        if field is None:
+                            continue
+
+                        # Get the related model
+                        if hasattr(field, 'related_model'):
+                            related_model = field.related_model
+                        elif hasattr(field, 'model'):
+                            related_model = field.model
+                        else:
+                            continue
+
+                        related_model_name = related_model.__name__
+
+                        # Find the reverse relationship name
+                        reverse_relationship_name = self._find_reverse_relationship(
+                            related_model, original_model, relationship_name
+                        )
+
+                        if reverse_relationship_name:
+                            # Add the reverse path
+                            if related_model_name not in graph:
+                                graph[related_model_name] = []
+
+                            # The path back is just the reverse relationship name
+                            graph[related_model_name].append([reverse_relationship_name])
+
+                    except Exception as e:
+                        # Skip problematic relationships
+                        continue
+
+            except Exception as e:
+                # Skip problematic models
+                continue
+
+        return graph
+
+    def _find_reverse_relationship(self, from_model, to_model, original_relationship_name):
+        """
+        Find the reverse relationship name from from_model to to_model.
+
+        Args:
+            from_model: The model to search relationships from
+            to_model: The target model to find relationship to
+            original_relationship_name: The original relationship name for context
+
+        Returns:
+            str or None: The reverse relationship name if found
+        """
+        try:
+            for field in from_model._meta.get_fields():
+                # Check ForeignKey, OneToOneField fields
+                if hasattr(field, 'related_model') and field.related_model == to_model:
+                    # Check if this field has a related_name that matches our original relationship
+                    if hasattr(field, 'related_name') and field.related_name == original_relationship_name:
+                        # This is the reverse of our original relationship
+                        return field.name
+                    elif not hasattr(field, 'related_name') or field.related_name is None:
+                        # Default reverse relationship name
+                        default_name = f"{to_model._meta.model_name}"
+                        if default_name == original_relationship_name.rstrip('s'):  # Simple heuristic
+                            return field.name
+
+                # Check reverse relationships
+                if hasattr(field, 'field') and hasattr(field.field, 'model'):
+                    if field.field.model == to_model:
+                        if field.get_accessor_name() == original_relationship_name:
+                            return field.field.name
+
+        except Exception:
+            pass
+
+        return None
+
+    def get_relationships(self, model_name: str) -> List[str]:
+        """
+        Get the list of direct relationships for a given model name.
+
+        Args:
+            model_name (str): The name of the model to look up
+
+        Returns:
+            List[str]: List of relationship names for the model.
+                      Returns empty list if model is not found.
+        """
+        return self._model_relationships.get(model_name, [])
+
+    def get_relationship_paths(self, model_name: str) -> List[List[str]]:
+        """
+        Get all relationship paths for a given model name.
+        This includes both direct relationships and reverse paths.
+
+        Args:
+            model_name (str): The name of the model to look up
+
+        Returns:
+            List[List[str]]: List of relationship paths (each path is a list of relationship names).
+                            Returns empty list if model is not found.
+        """
+        return self._relationship_graph.get(model_name, [])
+
+    def get_relationship_graph(self) -> Dict[str, List[List[str]]]:
+        """
+        Get the complete relationship graph.
+
+        Returns:
+            Dict[str, List[List[str]]]: The complete relationship graph
+        """
+        return self._relationship_graph.copy()
+
+
+# Create a singleton instance to use throughout the application
+sync_model_manager = SyncModelChildrenManager()
diff --git a/sync/signals.py b/sync/signals.py
index b49371a..7e275a8 100644
--- a/sync/signals.py
+++ b/sync/signals.py
@@ -11,6 +11,8 @@ from .ws_sender import websocket_sender
 from .registry import device_registry, related_users_registry
 
 import logging
+import sys
+import traceback
 
 logger = logging.getLogger(__name__)
 
@@ -21,31 +23,41 @@ User = get_user_model()
 @receiver([pre_save, pre_delete])
 def presave_handler(sender, instance, **kwargs):
 
-    # some other classes are excluded in settings_app.py: SYNC_APPS
-    if not isinstance(instance, (BaseModel, User)):
-        return
-
-    signal = kwargs.get('signal')
-    # avoid crash in manage.py createsuperuser + delete user in the admin
-    if isinstance(instance, User) and (instance._state.db is None or signal == pre_delete):
-        return
+    try:
+        # some other classes are excluded in settings_app.py: SYNC_APPS
+        if not isinstance(instance, (BaseModel, User)) or isinstance(instance, DataAccess):
+            return
 
-    users = related_users(instance)
+        signal = kwargs.get('signal')
+        # avoid crash in manage.py createsuperuser + delete user in the admin
+        if isinstance(instance, User) and (instance._state.db is None or signal == pre_delete):
+            return
 
-    related_users_registry.register(instance.id, users)
-    # user_ids = [user.id for user in users]
+        users = related_users(instance)
 
+        related_users_registry.register(instance.id, users)
+
+        if signal == pre_save:
+            detect_foreign_key_changes_for_shared_instances(sender, instance)
+            sig_type = 'pre_save'
+        elif signal == pre_delete:
+            # if hasattr(instance, 'id'):
+            #     try:
+            #         data_access_list = DataAccess.objects.filter(model_id=instance.id)
+            #         if data_access_list:
+            #             logger.info(f'>>> {instance.__class__.__name__} {instance.id} : delete {data_access_list.count()} DataAccess')
+            #         data_access_list.delete()
+            #     except Exception as e:
+            #         logger.info(f'*** ERRRRRRR: {e}')
+            #         logger.info(traceback.format_exc())
+            #         raise
+
+            sig_type = 'pre_delete'
+        # logger.info(f'* {sig_type} : {instance.__class__.__name__} > impacted users = {users}')
 
-    if signal == pre_save:
-        detect_foreign_key_changes_for_shared_instances(sender, instance)
-        sig_type = 'pre_save'
-    elif signal == pre_delete:
-        if hasattr(instance, 'id'):
-            data_access_list = DataAccess.objects.filter(model_id=instance.id)
-            logger.info(f'>>> delete {data_access_list.count()} DataAccess')
-            data_access_list.delete()
-        sig_type = 'pre_delete'
-    # logger.info(f'* {sig_type} : {instance.__class__.__name__} > impacted users = {users}')
+    except Exception as e:
+        logger.info(f'*** ERROR: {e}')
+        raise
 
 @receiver([post_save, post_delete])
 def synchronization_notifications(sender, instance, created=False, **kwargs):
@@ -59,47 +71,31 @@ def synchronization_notifications(sender, instance, created=False, **kwargs):
     if not isinstance(instance, BaseModel) and not isinstance(instance, User):
         return
 
-    process_foreign_key_changes(sender, instance, **kwargs)
-
-    signal = kwargs.get('signal')
-    save_model_log_if_possible(instance, signal, created)
-    notify_impacted_users(instance)
-
-    related_users_registry.unregister(instance.id)
+    try:
+        process_foreign_key_changes(sender, instance, **kwargs)
+        signal = kwargs.get('signal')
+        save_model_log_if_possible(instance, signal, created)
+        notify_impacted_users(instance)
+        related_users_registry.unregister(instance.id)
+    except Exception as e:
+        logger.info(f'*** ERROR2: {e}')
+        logger.info(traceback.format_exc())
+        raise
 
 def notify_impacted_users(instance):
-    # print(f'*** notify_impacted_users for instance: {instance}')
-    # user_ids = set()
-    # # add impacted users
-    # if isinstance(instance, User):
-    #     user_ids.add(instance.id)
-    # elif isinstance(instance, BaseModel):
-    #     owner = instance.last_updated_by
-    #     if owner:
-    #         user_ids.add(owner.id)
-
-    # if isinstance(instance, BaseModel):
-    #     if hasattr(instance, '_users_to_notify'):
-    #         user_ids.update(instance._users_to_notify)
-    #     else:
-    #         print('no users to notify')
-
     device_id = device_registry.get_device_id(instance.id)
     users = related_users_registry.get_users(instance.id)
 
     if users:
         user_ids = [user.id for user in users]
         websocket_sender.send_message(user_ids, device_id)
-        # print(f'notify device: {device_id}, users = {user_ids}')
-        # for user_id in user_ids:
-        #     websocket_sender.send_user_message(user_id, device_id)
 
     device_registry.unregister(instance.id)
 
 def save_model_log_if_possible(instance, signal, created):
 
     users = related_users_registry.get_users(instance.id)
-    logger.debug(f'*** save_model_log_if_possible >>> users from registry = {users}, instance = {instance}')
+    # logger.info(f'*** save_model_log_if_possible >>> users from registry = {users}, instance = {instance}')
 
     if not users:
         logger.warning(f'!!! Registry returned empty users for instance {instance.id} ({instance.__class__.__name__})')
@@ -121,8 +117,8 @@ def save_model_log_if_possible(instance, signal, created):
         if isinstance(instance, SideStoreModel):
             store_id = instance.store_id
 
-        if operation == ModelOperation.DELETE: # delete now unnecessary logs
-            ModelLog.objects.filter(model_id=instance.id).delete()
+        # if operation == ModelOperation.DELETE: # delete now unnecessary logs
+            # ModelLog.objects.filter(model_id=instance.id).delete()
 
         # user_ids = [user.id for user in users]
         # # print(f'users to notify: {user_ids}')
@@ -133,16 +129,14 @@ def save_model_log_if_possible(instance, signal, created):
         logger.info(f'!!! Model Log could not be created because no linked user could be found: {instance.__class__.__name__} {instance}, {signal}')
 
 def save_model_log(users, model_operation, model_name, model_id, store_id):
-
     device_id = device_registry.get_device_id(model_id)
-
     logger.info(f'*** creating ModelLogs for: {model_operation} {model_name} : {users}')
 
     try:
         with transaction.atomic():
             created_logs = []
             for user in users:
-                # logger.info(f'Creating ModelLog for user {user.id} ({user.username})')
+                # logger.info(f'Creating ModelLog for user {user.id} - user exists: {User.objects.filter(id=user.id).exists()}')
                 model_log = ModelLog(
                     user=user,
                     operation=model_operation,
@@ -152,20 +146,19 @@ def save_model_log(users, model_operation, model_name, model_id, store_id):
                     device_id=device_id
                 )
                 model_log.save()
+                # logger.info(f'ModelLog saved with ID: {model_log.id}')
                 created_logs.append(model_log.id)
-                # logger.info(f'Successfully created ModelLog {model_log.id}')
 
-            # logger.info(f'*** Successfully created {len(created_logs)} ModelLogs: {created_logs}')
+            # Immediate verification within transaction
+            immediate_count = ModelLog.objects.filter(id__in=created_logs).count()
+            # logger.info(f'*** Within transaction: Created {len(created_logs)}, found {immediate_count}')
 
-            # Verify ModelLogs were actually persisted
-            persisted_count = ModelLog.objects.filter(id__in=created_logs).count()
-            if persisted_count != len(created_logs):
-                logger.error(f'*** PERSISTENCE VERIFICATION FAILED! Created {len(created_logs)} ModelLogs but only {persisted_count} were persisted to database')
-            else:
-                logger.info(f'*** PERSISTENCE VERIFIED: All {persisted_count} ModelLogs successfully persisted')
+        # Verification after transaction commits
+        persisted_count = ModelLog.objects.filter(id__in=created_logs).count()
+        # logger.info(f'*** After transaction: Created {len(created_logs)}, persisted {persisted_count}')
 
     except Exception as e:
-        logger.error(f'*** FAILED to create ModelLogs for: {model_operation} {model_name}, users: {[u.id for u in users]}, error: {e}', exc_info=True)
+        logger.error(f'*** Exception during ModelLog creation: {e}', exc_info=True)
         raise
 
     # with transaction.atomic():
@@ -209,7 +202,6 @@ def detect_foreign_key_changes_for_shared_instances(sender, instance):
         return
 
     data_access_list = related_data_access(instance)
-    # print(f'FK change > DA count = {len(data_access_list)}')
     if data_access_list:
         try:
             old_instance = sender.objects.get(pk=instance.pk)
@@ -278,12 +270,12 @@ def process_foreign_key_changes(sender, instance, **kwargs):
 
 ### Data Access
 
-# @receiver(post_delete)
-# def delete_data_access_if_necessary(sender, instance, **kwargs):
-#     if not isinstance(instance, BaseModel):
-#         return
-#     if hasattr(instance, 'id'):
-#         DataAccess.objects.filter(model_id=instance.id).delete()
+@receiver(post_delete)
+def delete_data_access_if_necessary(sender, instance, **kwargs):
+    if not isinstance(instance, BaseModel):
+        return
+    if hasattr(instance, 'id'):
+        DataAccess.objects.filter(model_id=instance.id).delete()
 
 @receiver(m2m_changed, sender=DataAccess.shared_with.through)
 def handle_shared_with_changes(sender, instance, action, pk_set, **kwargs):
@@ -309,26 +301,41 @@ def handle_shared_with_changes(sender, instance, action, pk_set, **kwargs):
 
 @receiver(post_save, sender=DataAccess)
 def data_access_post_save(sender, instance, **kwargs):
-    instance.add_references() # create DataAccess references on hierarchy
+    try:
+        instance.add_references() # create DataAccess references on hierarchy
 
-    if instance.related_user:
-        evaluate_if_user_should_sync(instance.related_user)
+        if instance.related_user:
+            evaluate_if_user_should_sync(instance.related_user)
+    except Exception as e:
+        logger.info(f'*** ERROR3: {e}')
+        logger.info(traceback.format_exc())
+        raise
 
 @receiver(pre_delete, sender=DataAccess)
 def revoke_access_after_delete(sender, instance, **kwargs):
-    instance.cleanup_references()
-    instance.create_revoke_access_log()
-    related_users_registry.register(instance.id, instance.shared_with.all())
+    try:
+        instance.cleanup_references()
+        instance.create_revoke_access_log()
+        related_users_registry.register(instance.id, instance.shared_with.all())
 
-    instance._user = instance.related_user
+        instance._user = instance.related_user
+    except Exception as e:
+        logger.info(f'*** ERROR4: {e}')
+        logger.info(traceback.format_exc())
+        raise
 
 @receiver(post_delete, sender=DataAccess)
 def data_access_post_delete(sender, instance, **kwargs):
-    notify_impacted_users(instance)
+    try:
+        notify_impacted_users(instance)
 
-    if not hasattr(instance, '_user') or not instance._user:
-        return
-    evaluate_if_user_should_sync(instance._user)
+        if not hasattr(instance, '_user') or not instance._user:
+            return
+        evaluate_if_user_should_sync(instance._user)
+    except Exception as e:
+        logger.info(f'*** ERROR5: {e}')
+        logger.info(traceback.format_exc())
+        raise
 
 def related_users(instance):
     users = set()
@@ -373,9 +380,14 @@ def evaluate_if_user_should_sync(user):
 
 @receiver(post_save, sender=Device)
 def device_created(sender, instance, **kwargs):
-    if not instance.user:
-        return
-    evaluate_if_user_should_sync(instance.user)
+    try:
+        if not instance.user:
+            return
+        evaluate_if_user_should_sync(instance.user)
+    except Exception as e:
+        logger.info(f'*** ERROR6: {e}')
+        logger.info(traceback.format_exc())
+        raise
 
 @receiver(pre_delete, sender=Device)
 def device_pre_delete(sender, instance, **kwargs):
@@ -383,6 +395,11 @@ def device_pre_delete(sender, instance, **kwargs):
 
 @receiver(post_delete, sender=Device)
 def device_post_delete(sender, instance, **kwargs):
-    if not hasattr(instance, '_user') or not instance._user:
-        return
-    evaluate_if_user_should_sync(instance._user)
+    try:
+        if not hasattr(instance, '_user') or not instance._user:
+            return
+        evaluate_if_user_should_sync(instance._user)
+    except Exception as e:
+        logger.info(f'*** ERROR7: {e}')
+        logger.info(traceback.format_exc())
+        raise
diff --git a/sync/utils.py b/sync/utils.py
index ee7ff80..07168bf 100644
--- a/sync/utils.py
+++ b/sync/utils.py
@@ -50,6 +50,7 @@ class HierarchyOrganizer:
     def __init__(self):
         self.levels = []  # List of dictionaries, each representing a level
         self.item_levels = {}  # Keep track of items and their levels: (model_name, id) -> level
+        self.sharing_related_instances = {}  # Keep track of items and their levels: (model_name, id) -> level
 
     def add_item(self, model_name, item_data, level):
         """
diff --git a/sync/views.py b/sync/views.py
index 3f27041..c4dd8e3 100644
--- a/sync/views.py
+++ b/sync/views.py
@@ -24,6 +24,10 @@ from .models import ModelLog, BaseModel, SideStoreModel, DataAccess
 from .registry import model_registry, device_registry
 from .ws_sender import websocket_sender
 
+import logging
+
+logger = logging.getLogger(__name__)
+
 # class HierarchyApiView(APIView):
 
 def add_children_hierarchy(instance, models_dict):
@@ -358,21 +362,32 @@ class LogProcessingResult:
         revocations = defaultdict(list)
         revocations_parents_organizer = HierarchyOrganizer()
 
-        # print(f'*** process_revocations: {len(self.revoke_info)}')
+        # logger.info(f'$$$ process_revocations: {len(self.revoke_info)}')
+        sync_models = getattr(settings, 'SYNC_MODEL_CHILDREN_SHARING', {})
 
         # First, collect all revocations
         for model_name, items in self.revoke_info.items():
             revocations[model_name].extend(items)
 
-            # print(f'*** process_revocations for {model_name}')
+            logger.info(f'$$$ process_revocations for {model_name}, items = {len(items)}')
 
             # Process parent hierarchies for each revoked item
             model = model_registry.get_model(model_name)
             for item in items:
+
+                logger.info(f'$$$ item revoked = {item}')
+
                 try:
                     instance = model.objects.get(id=item['model_id'])
-                    # print(f'*** process revoked item parents of {model_name} : {item['model_id']}')
+                    logger.info(f'$$$ process revoked item parents of {model_name} : {item['model_id']}')
                     add_parents_with_hierarchy_organizer(instance, revocations_parents_organizer)
+
+                    # if instance.__class__.__name__ in sync_models:
+                    #     sharing_related_instances = sharing_related_instances(instance, True)
+                    #     logger.info(f'$$$ get shared instances: {len(sharing_related_instances)}')
+                    #     revocations = merge_dicts_dedup(revocations, sharing_related_instances)
+                    #     # revocations_parents_organizer.sharing_related_instances = instance.sharing_related_instances()
+
                 except model.DoesNotExist:
                     pass
 
@@ -387,6 +402,8 @@ class LogProcessingResult:
         # print(f'self.shared_relationship_sets = {self.shared_relationship_sets}')
         # print(f'self.shared_relationship_removals = {self.shared_relationship_removals}')
 
+        logger.info('--------------------- SYNC')
+
         return {
             "updates": dict(self.updates),
             "deletions": dict(self.deletions),
@@ -451,3 +468,61 @@ class DataAccessViewSet(viewsets.ModelViewSet):
         if self.request.user:
             return self.queryset.filter(Q(related_user=self.request.user) | Q(shared_with__in=[self.request.user]))
         return []
+
+def merge_dicts_dedup(dict1, dict2):
+    """Merge two dictionaries, combining arrays and removing duplicates"""
+    all_keys = set(dict1.keys()) | set(dict2.keys())
+
+    merged = {}
+    for key in all_keys:
+        arr1 = dict1.get(key, [])
+        arr2 = dict2.get(key, [])
+        # Convert to sets, union them, then back to list to remove duplicates
+        merged[key] = list(set(arr1) | set(arr2))
+
+    return merged
+
+def sharing_related_instances(instance, identifiers_only):
+
+    sync_models = getattr(settings, 'SYNC_MODEL_CHILDREN_SHARING', {})
+    # if self.__class__.__name__ in sync_models:
+    relationships = sync_models[instance.__class__.__name__]
+    #     'Match': {'team_scores', 'team_registration', 'player_registrations'}
+
+    models_dict = defaultdict(dict)
+
+    print(f'relationships = {relationships}')
+    current = [instance]
+    for relationship in relationships:
+        print(f'> relationship = {relationship}')
+        values = []
+        for item in current:
+            value = getattr(item, relationship)
+
+            if hasattr(value, 'all') and callable(value.all):
+                # This is a queryset from a reverse relationship
+                for related_obj in value.all():
+                    child_model_name = related_obj.__class__.__name__
+                    if identifiers_only:
+                        models_dict[child_model_name].append(related_obj.data_identifier_dict())
+                    else:
+                        serializer = get_serializer(related_obj, child_model_name)
+                        models_dict[child_model_name].append(serializer.data)
+                        # print(f'>>> 1 Added child for {relationship}: {child_model_name}')
+                values.extend(value.all())
+            else:
+                # This is a single object
+                child_model_name = value.__class__.__name__
+                if identifiers_only:
+                    models_dict[child_model_name].append(value.data_identifier_dict())
+                else:
+                    serializer = get_serializer(value, child_model_name)
+                    models_dict[child_model_name].append(serializer.data)
+
+                # serializer = get_serializer(value, child_model_name)
+                # models_dict[child_model_name][value.id] = serializer.data
+                # print(f'>>> 2 Added child for {relationship}: {child_model_name}')
+
+                values.append(value)
+        current = values
+    return models_dict
diff --git a/tournaments/models/match.py b/tournaments/models/match.py
index 25f0a15..af8660c 100644
--- a/tournaments/models/match.py
+++ b/tournaments/models/match.py
@@ -1,7 +1,9 @@
 from django.db import models
-# from tournaments.models import group_stage
-from . import TournamentSubModel, Round, GroupStage, FederalMatchCategory
 from django.utils import timezone, formats
+from django.core.exceptions import ObjectDoesNotExist
+
+from . import TournamentSubModel, Round, GroupStage, FederalMatchCategory
+
 from datetime import datetime, timedelta
 
 import uuid
@@ -90,14 +92,16 @@ class Match(TournamentSubModel):
             return '--'
 
     def stage_name(self):
-        if self.name:
-            return self.name
-        elif self.round:
-            return self.round.name()
-        elif self.group_stage:
-            return self.group_stage.display_name()
-        else:
-            return '--'
+        try:
+            if self.name:
+                return self.name
+            elif self.round:
+                return self.round.name()
+            elif self.group_stage:
+                return self.group_stage.display_name()
+        except ObjectDoesNotExist:
+            pass
+        return "--"
 
     def get_previous_round(self):
         # Calculate the next index
diff --git a/tournaments/models/team_score.py b/tournaments/models/team_score.py
index 14765a6..b4845ff 100644
--- a/tournaments/models/team_score.py
+++ b/tournaments/models/team_score.py
@@ -1,4 +1,6 @@
 from django.db import models
+from django.core.exceptions import ObjectDoesNotExist
+
 from . import TournamentSubModel, Match, TeamRegistration, FederalMatchCategory
 import uuid
 from .match import Team  # Import Team only when needed
@@ -15,10 +17,14 @@ class TeamScore(TournamentSubModel):
         pass
 
     def __str__(self):
-        if self.match:
-            return f"{self.match.stage_name()} #{self.match.index}: {self.player_names()}"
-        else:
-            return "Empty"
+        try:
+            if self.match and self.team_registration:
+                return f"{self.match.stage_name()} #{self.match.index}: {self.player_names()}"
+            if self.match:
+                return f"{self.match.stage_name()} #{self.match.index}"
+        except ObjectDoesNotExist:
+            pass
+        return "--"
 
     def get_tournament(self): # mandatory method for TournamentSubModel
         if self.team_registration:
@@ -48,14 +54,16 @@ class TeamScore(TournamentSubModel):
     #         return None
 
     def player_names(self):
-        if self.team_registration:
-            if self.team_registration.name:
-                return self.team_registration.name
-            else:
-                names = self.team_registration.team_names()
-                return " - ".join(names)
-        else:
-            return "--"
+        try:
+            if self.team_registration: # this can cause an exception when deleted
+                if self.team_registration.name:
+                    return self.team_registration.name
+                else:
+                    names = self.team_registration.team_names()
+                    return " - ".join(names)
+        except TeamRegistration.DoesNotExist:
+            pass
+        return "--"
 
     def shortened_team_names(self, forced=False):
         names = []