The Sena Pi only allows a 2-way intercom with another Pi.

However, the non-Evo cycling helmets R1, R2 and M1 allow up to 4-way intercom with another helmets.

First, are all those helmets inter-compatible? Let's say, can the R1 connect with one R2 and one M1 in a 3-way intercom?

Second, can those helmets connect with a Pi? If they can, and since they support 4-way intercom, does that mean that they could connect with up to 3 other Pi and have all of them together in a common communication with the helmet as central point?

Thanks a lot for your support.