Thanks for taking the time for the explanation. Maybe I was looking for the wrong words (like: sequential jms) because I did use the search engine... I searched for an hour without finding anything useful. Please don't think that I easily post such questions on this forum because I know that you JBoss guys have a lot to do. I need to study you solution a bit more because I don't understand several things about it. Like: - Why do I need a topic? Isn't a queue enough because a message only needs to be processed by one receiver? - Do I need to configure a invoke-proxy-binding for every customer? I do have 700.000 customers, and those can be added dynamically... I thought that the solution would be like a cluster wide locking mechanism. This is what I mean: - A message comes in to the message queue with a certain customer id property - For this id a lock is acquired via the cluster wide singleton locking mechanism by the MB - The next message for this id is received while the other is still being processed - The process for the second message tries to acquire a lock, but needs to wait for the other process to finish for this id. - The moment the lock is released the next process in line receives the lock and can start processing. In this case the second process. Is this a stupid idea? Am I missing something about the whole JMS technology? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4067691#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...