As far as I've tried out, there is no possiblity to
broadcastevents from one session to another one. The first thing you can do is to use an application scoped bean which processes events and re-sends them to other session. I've done this in combination with ajax-poll, whic triggers a rerender after receiving an event (you need an eventListener, which is the application scoped bean, which listens to events).
Another approch I used is using JMS for relaying session-scoped events to the application. It's a bit more alaborate, but the big advantage is that you can
filtermessage-reception, and you can also heve MDB's listen to events and (in my case a requirement) also remote java-clients listening to a Topic.