group collaborating notification

application/Espo/Tools/Notification/CollaboratorsNotificator.php

@@ -80,6 +80,8 @@ class CollaboratorsNotificator
                 'createdByName' => $this->user->getName(),
             ])
             ->setRelated(LinkParent::fromEntity($entity))
+            // Needed for grouping.
+            ->setRelatedParent(LinkParent::fromEntity($entity))
             ->setActionId($params->getActionId());
 
         $this->entityManager->saveEntity($notification);

application/Espo/Tools/Notification/RecordService.php

@@ -924,6 +924,7 @@ class RecordService
         return [
             Notification::TYPE_NOTE,
             Notification::TYPE_USER_REACTION,
+            Notification::TYPE_COLLABORATING,
             'EventAttendee',
         ];
     }