If I am getting your requirement correct, you want to requeue the items based on the flag.
You can call QueueforAgent method again in the last step of the agent activity ProcessPartyMgtEvents. You can add a last conditional step in the activity for the method QueueforAgent. That should again queue those items.
I am not sure thats what you want to achieve.
Ideally if a item gets into broken process queue if it failed to complete the operation. But as per your descriptions you want to requeue the successful items .
Please let me know if that helps or want further information.