Assign multiple tasks - JEE component needed in OSGI

In OSGI, we need the ability to assign tasks to multiple people in parallel.  This list of users is dynamically retreived from a database but, this is not a problem in itself.

The step needs to assign tasks to each user.

If any of the users "action" the task positively, it queues and waits for the others to respond.

If ALL users "action" the task positively, the workflow moves forward.

If any of the users "action" the task negatively, it will kill the other users' tasks and move forward in the workflow.

We're ready to write a custom component for this functionality but, we have never written a component that blocks the workflow to assign tasks.  I'm also assuming that there is an API to assign tasks with Adaptive Forms.

Any advice on this complex topic would be appreciated.

Thanks,