A first mobile radio that is a member of a first talkgroup, the first mobile radio comprising: an infrastructure wireless communication interface for communicating with an infrastructure radio access network; a short-range wireless communication interface for communicating with an ad-hoc network; a processor; and data storage containing instructions executable by the processor for causing the first mobile radio to carry out a set of functions, the set of functions comprising: receiving, via a provisioning process or via the infrastructure wireless communication interface from the RAN while within wireless communication range of the RAN, a talkgroup-specific security token associated with and shared by all group mobile radios in a first talkgroup to which the first mobile radio is subscribed via the infrastructure wireless communication interface and RAN; detecting, via the short-range wireless communication interface, a second mobile radio; authenticating, via the short-range wireless communication interface, the second mobile radio using the talkgroup-specific security token and, when successful, adding an identity of the second mobile radio to a sub-talkgroup set of mobile radios of the first talkgroup, and selectively transmitting one or more of voice data, image data, and video data to one of the first talkgroups via the infrastructure wireless communication interface and the sub-talkgroup set of mobile radios of the first talkgroup via the short-range wireless communication interface as a function of a detected user interface input state detected at the first mobile radio. an infrastructure wireless communication interface for communicating with an infrastructure radio access network; a short-range wireless communication interface for communicating with an ad-hoc network; a processor; and data storage containing instructions executable by the processor for causing the first mobile radio to carry out a set of functions, the set of functions comprising: receiving, via a provisioning process or via the infrastructure wireless communication interface from the RAN while within wireless communication range of the RAN, a talkgroup-specific security token associated with and shared by all group mobile radios in a first talkgroup to which the first mobile radio is subscribed via the infrastructure wireless communication interface and RAN; detecting, via the short-range wireless communication interface, a second mobile radio; authenticating, via the short-range wireless communication interface, the second mobile radio using the talkgroup-specific security token and, when successful, adding an identity of the second mobile radio to a sub-talkgroup set of mobile radios of the first talkgroup, and selectively transmitting one or more of voice data, image data, and video data to one of the first talkgroups via the infrastructure wireless communication interface and the sub-talkgroup set of mobile radios of the first talkgroup via the short-range wireless communication interface as a function of a detected user interface input state detected at the first mobile radio. receiving, via a provisioning process or via the infrastructure wireless communication interface from the RAN while within wireless communication range of the RAN, a talkgroup-specific security token associated with and shared by all group mobile radios in a first talkgroup to which the first mobile radio is subscribed via the infrastructure wireless communication interface and RAN; detecting, via the short-range wireless communication interface, a second mobile radio; authenticating, via the short-range wireless communication interface, the second mobile radio using the talkgroup-specific security token and, when successful, adding an identity of the second mobile radio to a sub-talkgroup set of mobile radios of the first talkgroup, and selectively transmitting one or more of voice data, image data, and video data to one of the first talkgroups via the infrastructure wireless communication interface and the sub-talkgroup set of mobile radios of the first talkgroup via the short-range wireless communication interface as a function of a detected user interface input state detected at the first mobile radio.