Communication with any other rider with a Kenwood is very very simple. You just both select the same pre-programmed channel frequency (numbered 1-13).
I met up with Greg Masters at the Ace some time ago and we were heading back to his house. He has his set-up permanently hard-wired to his bike. He had his daughter riding pillion. Lisa and I have portable bike-to-bike Autocom systems using Kenwoods. We all switched to Channel 1 and had 4-way conversation - Greg and daughter using VOX, Lisa and I using PTT. No problems whatsover.
If you're communicating with any other bike using non-Kenwood radios, as long as they are PRM466, you just need to insure you're on the same frequency. In some cases it can take a bit of fiddling finding one that you can all use. Obviously, a mix of Kenwoods, Icoms, and one or two other brands multiplies the complexity of getting it sorted from the off.
From experience, I've found that having more than about 4 or 5 of you on air can be too many - but it's great for two or three of you out on a ride.