This something I would love to do, however September is probably not going to suit me with getting married and all that month.
The lead car and the tail car really are the only ones that NEED a radio. Simple rule of always keeping the MR2 behind you in your mirror that applies to all but the tail car works very well, and means there is no need to be pulling over. It's ok to have the group stretched out points, as long as each of us can see the MR2 behind us. Even with this setup, radios are not essential