I can tell you what I've done and you can go from there.
I bought the Sena SMH10 blue-tooth headset. It can be paired with another Sena for helmet-to-helmet communications (actually, up to four helmets). It can also be paired to practically any other blue-tooth device, and I have mine paired to a Zumo 660 and an iPhone. With this simple setup, I can make and receive telephone calls, listen to music, receive audio from any app on my iPhone - like another navigation app (I use Motion X for trip info) or streaming audio, so I can listen to my favorite radio station anywhere that I can get a data signal. Additionally, the phone is paired to my Cobra iRadar, so I can get visual radar warnings on the phone.
And now I'm trying to find a small, portable blue-toothed CB unit so I can communicate with the sweep when leading a large group. Anyone know of such a thing?