If you are looking to sinc numerous riders the Sena 20S can link up to 9. It gets a little complicated and I agree that trying to communicate with that many people is distracting. I know that Danny & Elaine and Jan and I have all paired up and it works nice for 2 bikes with 2 up. Great for pottie breaks if you are not leading.
I think trip leader and sweep would be a really good idea.