FYI: Jamba does use party/raid for data communication. It falls back to whisper if the toons are not in a party/raid together.

The jamba team is online channel that you can specify in settings is only for toon online/offline management. If bob is in my jamba team list, I need to know whether or not bob is online. Sending bob a message when bob is offline results in yellow Player Not Found messages, which people really don't like. Not sure how the cross realm support will affect this issue.