A method of conserving battery power of mobile devices within a location-based group starts with server receiving location data and proximity information from each of the mobile devices. Location data received from first mobile device includes the first mobile device's location. Proximity information received from first mobile device includes an identification of mobile devices within a predetermined radius of first mobile device's location. Server identifies based on location data and proximity information a specific location and forms a subgroup of mobile devices that are within a predetermined radius of the specific location. Server queries and receives a level of power associated with each mobile devices in the subgroup and transmits control signals to each mobile devices in the subgroup to shut down radio functions based on the level of power. Other embodiments are also described.