I don't really understand what 'user' means but if it a simple ID you can use a JMS header for that
add a JMS property:
Then the MDB that gets message from Vicent can use a message selector:
"recipientId = 'Vincent'";
(if you have a standalone client, message selector can be specified when creating your queue receiver.
Hope it helps.
Thanks for your help!
I can solve my problem with your solution.