Need to be able to remove orphaned subscription threads

Occasionally, due to unknown causes (possible internal or communication errors) we end up with a subscription in a "zombie" state. We cannot start it (normally system complains it's running), stop it (normally system complains it's not running) or do any other action. This normally means that during some setup or processing one or more threads belonging to the subscription were left in either the source or target agent.
The existence of these threads prevent any subscription operation to be completed:
- A stop requires that the whole set of threads is running and responding
- A start requires no threads are already created as the existence of any threads will cause startup errors

This can be tricky to identify. A kill -3 to the agents processes will generate a javacore and we can manually check for any thread with the subscription name and prefix or suffix.
But even if a customer does that, then the only solution is to restart the agent. This has an obvious negative impact as they will stop all subscription running on that agent. On today's enterprise environment this typically requires a process, approvals etc. It's a complex, tedious and slow process. Ideally we should provide a tool (dmclearsubthreads?) that would forcibly remove all of a subscription's threads. The tool could have some checks in place, like refusing to do anything if the complete set of subscription threads is running, or eventually try to send some request and refuse to work if the request was answered as expected.