I'm using JBoss Messaging in version 1.4.x. I work in clustered environment. I have some number MDBs consuming messages from queue. This messages provide data to perform some operation on database. Unfortunately there is possibility that many of this messages will contain the same information and therefor they shouldn't be delivered at the same time. Do you know any solution which can prevent this kind of situation? Order of perform is not important, but every message should be delivered and performed. Lets suppose that I add some hash to every message which will allow to identify similar messages.