Data between two flash apps

Let’s say I have two flash apps, each being run by a separate user. Is it possible for user A to click a button and have a message pop up on user B’s screen? Assume I know the IP address of user B and can route the traffic to them.

I’m guessing, if this can be done, it would be accomplished using some type of EventListener, but I’m not sure where to start.

Any help is greatly appreciated.