We have a clustered JBoss-4.0.3 env
The site can never come down (well that is a requirement from up top..go figure..that critical :-)
Here is the issue:-
When it is time to upgrade/update with new ear, one set of clusters need to be brought down and be upgraded using session refusal to that cluster.
(In the meantime another set of clusters will be working serving the requests)

How can I do this? Where do I start??

<more info about the architecture:-
front end is cleanly seperated from the JBoss middleware...ie the struts portion is in Oregon and the backend JBoss servers are in New York.
>