I have thought of adding timeout support for multicast but haven't got around the time to do it. And haven't seen any requests for it.
Sometimes using regular Java is often easy so I would suggest to use a bean for the database work where you can do your own timeout check. For example loop X times and check for that database value changed. Using Spring JDBC is easy to invoke JDBC calls.
Thanks for the response.
For this effort, I'm trying to minimize custom code, so I'm going to give the aggregator EIP a try to see if I can use that correctly to correlate my InOut route with a polling db route (using something like a timer).