Here's how the group I'm in does it. Our people generally know how things go, but we do have a newbie once in a while. We place those guys near the front.
1. Driver's meeting. A rough convoy order is established and a rough idea of the route and stops along the way. Pace of the tour is established, usually no more than 20km/h over the speed limit
2. With a larger group, there's a lead, middle and sweep car. Having high visibility colours in those positions help.
3. Each car ideally has a CB Radio. We also have a couple of loaner units on hand. If not possible, CBs should be in the lead, middle and sweep positions.
4. Fast drivers to the
back. They can choose to slow down and then drive faster to catch up if they wish. This means no pressure on newbies or slower cars to catch up. We haven't had a case where there has been a huge differential in speed from front to back, so YMMV.
5. At turns, especially hidden ones, one car stays behind to make sure people see the turn.
6. We have no rules regarding passing, we use common sense. The lead car calls out oncoming traffic on the CB if we're on two lane roads so we can pass parties not in our group. The lead car also calls out road hazards (dips, potholes, train tracks etc.) The sweep car continually calls out when all cars have made it around a corner, or how many cars are caught at a light etc.