[rules-users] Drools in multithreaded env

Env setup: 1. There is only one instance of working memory. 2. There are at lease two threads constantly insert/update/delete facts from the same workings memory based on some incoming messages. 3. I use temporal rules (duration clause) as well. When it is fired, it will be on the third thread. Question: I can synchronize the first two threads by acquiring lock on the working memory. But how do I synchronize the temporal rules thread especially on the left hand side of the rules? Thanks, Jin