You are rite Jonathan, actually what I am doing is
1-> I am picking the data from DB in batches and pushing into 1 queue on UM along with that assigning unique Id to the batches.
2-> Once all the batches I have pushed to UM then I am pushing one more message which is having only unique Id.
And I have configured trigger for 2nd step which will extract the unique Id from the queue and pull all the messages from the 2nd queue matching the unique Ids using pub.jms:receive in that trigger service only.
#webMethods#Integration-Server-and-ESB#Universal-Messaging-Broker