I've found the best success when shooting in a group is when we all have a pre-agreed upon subject or group of subjects in a single location. Then we can all work around the same subject and we tend to feed off each other's creative vibes. What doesn't work is cruising around together looking for something, because invariably the one driving the car has a different interest than the one(s) in the passenger seat, and either the driver gets forced to stop for something they aren't up for, or the passengers get stiffed out of shooting something because the driver won't stop.