'Private' messages in Exodus

I'd like to be able to deliver messages to Jabber clients and have a custom plugin control the UI appearance. I.e. I don't want message dialogs or headline alert dialogs. For example when an instrument sends a 'private message'to the jabber client, I want to present a custom dialog.

Does anyone know of any way of accomplishing this either using IExdousController or Message Types?
I've implemented the IExodusPlugin.Process method so I can capture the packets. Just need a way of inhibiting the various popups. (Would prefer not to modify the client source)
-Fred