Waiting callback to Flowable from external service

Flowable Engine
1

Hi Flowable team!
I have a process that consists of three steps:

  1. Sending document data to an external system (my separate DeliveryService is responsible for sending this data).
  2. Sending additional data of this document to the external system (also handled by my DeliveryService).
  3. Waiting for a callback from the DeliveryService for up to 10 minutes, confirming that the document upload operation was completed successfully.
    The DeliveryService first receives the callback from the external system and then should call back my workflow engine to complete this third step.

For the first two tasks, I used External Worker Tasks, so the service with the Flowable workflow engine sends data to a topic, and my DeliveryService acts as a FlowableWorker.

However, I’m not sure what’s the best way to implement the third step.
I considered defining it as a Receive Task and using the endpoint
PUT /process-api/runtime/executions/{executionId} with "action": "trigger" to trigger this task.
But my DeliveryService should not be aware of the executionId.

Could you please suggest a suitable solution for this case?

Best regards, Evelina T.