Boy that is a tough situation! I am thinking like Tartan that when you all get there the leader should just do some housekeeping tips/rules and mention that everyone is there to get things done and have fun working on THEIR projects. Maybe you could mention that in the evening (or whatever time) that after lunch/dinner that you can set aside an hour for anyone wanting to participate in lending a hand or giving/getting help but that it is strictly on a voluntary basis.