Enhancement: mergeable bulk edit permissions (#5508)

src/documents/serialisers.py

@@ -916,6 +916,8 @@ class BulkEditSerializer(DocumentListSerializer, SetPermissionsMixin):
         )
         if "owner" in parameters and parameters["owner"] is not None:
             self._validate_owner(parameters["owner"])
+        if "merge" not in parameters:
+            parameters["merge"] = False
 
     def validate(self, attrs):
         method = attrs["method"]
@@ -1258,6 +1260,12 @@ class BulkEditObjectPermissionsSerializer(serializers.Serializer, SetPermissions
         write_only=True,
     )
 
+    merge = serializers.BooleanField(
+        default=False,
+        write_only=True,
+        required=False,
+    )
+
     def get_object_class(self, object_type):
         object_class = None
         if object_type == "tags":