How do I differentiate between MQTT Publish events originating from Users vs internal messages meant to broadcast only

_x000D_ _x000D_ I am using mosquitto mqtt client. For example, you have users that publish and subscribe to topics. The topic actually correlates to a REsT endpoint. Scenario 1 (typical pub/sub usage) UserA subscribes to topic /device/123/meta UserB publishes some data to topic /device/123/meta by definition, this publish is broadcasted out to the subscribers we have a script subscribed to /devices/# which knows how to save the payload for the topic /device/123/meta when it receives publish'ed data. This data is saved to the database. Scenario 2 Someone updates data /device/123/meta via a ReST interface (or a direct DB update, the key is it's not a MQTT publish). database is updated a publish message is sent to the MQTT broker so that all subscribers get the updates as a payload Scenario 2 is what I'm trying to wrap my head around. This creates a nasty feedback loop. When internal messages are broadcasted out, my script to deal with publish events from users can't differentiate between publish events originating from a 3rd party user or an internal publish event only meant to broadcast out some data (with no saving of data needed). How should I handle this? The MQTT message is very simplistic and I'm not finding anything I can base logic off of. I'm trying to explore using the origin somehow, but no luck this far. I realize I can write plugins, but this is quite the task for mosquitto.