A controller in a network assigns a dedicated foreign radio talk group to each radio frequency (RF) site in the network for use by foreign radios during an incident event. The controller receives a registration request from a foreign radio and registers the foreign radio in a first RF site. The controller receives a talk group affiliation request from the foreign radio and, responsive to determining that the first RF site is in the incident event mode, affiliates the foreign radio with dedicated foreign radio talk group that is assigned to the first RF site, associated with at least one of a system identifier, a Wide Area Communication Network identifier and a talk group identifier provided by the foreign radio, and/or associated with the talk group identifier provided by the foreign radio and included in a master list including talk group IDs associated with a function.