How can I get this done???
You can't. Session information is scoped to the current ServletContext, and there is one ServletContext per web app. ServletContext information is not designed to be shared.
One question which jumps out is if you have stuff in the session needed by both web apps, why do you have two web apps at all? Couldn't you combine them into one?
If you can't, you could just pass this info with the request.