1) Designate a trail boss. The trail boss should pick the tail gunner and if the group is large enough maybe a waist gunner as well. At the very least these three people should have communications with each other. If the group is large and has varied capabilities you might consider splitting into two seperate groups.
2) Have a driver's meeting where everyone introduces themselves everyone does not know each other. The trail boss should talk about what to expect for the day in terms of length (distance and time) and difficulty.
3) Alternate more and less capable vehicles and vehicles with and without winches if at all possible to keep the group moving through difficult sections.
4) The group should not split up if possible, but the trail boss should also make an effort to keep the group moving along. It seems that as group size increases time to get anywhere grows exponentially. If someone has a minor problem or needs to go to the bathroom or something I recommend that the tail gunner stay with them and the rest of the group keep moving. The stragglers should be able to catch up at the next difficult section.
5) If there are any forks in the road the trail boss should relay back to the waist gunner and tail gunner to let them know which way to go, and each if the group is all together each vehicle should stop and confirm that the vehicle behind them went the right way.
How is that for a start?