After the initial contact has been established, a scheduled communications plan to exchange info every 6 hrs would be a smart move.

This would save power and keep your group and other groups updated on weather conditions at each transmitting location, any observed movements by unknown groups, any critical medical issues occurring (disease or illness) that a group is experiencing, any supply shortages each group is looking to fill (bartering), etc.

This would have all groups better informed of their surroundings and the various pertinent situations of like minded neighbors.