A method for automatic configuration of virtual talk groups based on location of media source includes monitoring communications from a plurality of mobile endpoints. Each communication comprises a media message and location information identifying a location of its transmitting endpoint. The method includes selecting a first group of mobile endpoints of the plurality of endpoints according to virtual talk group configuration instructions based on the locations of the mobile endpoints. The method also includes configuring a first virtual talk group comprising the first group of mobile endpoints to facilitate communications among the first group of mobile endpoints. The first group of mobile endpoints comprises mobile endpoints of different communication networks.