An exemplary embodiment of the invention relates to configuring the minimum number of relay radios in a live-virtual communications system for a tactical training event. The system includes live radios, virtual radios cooperating with a wide area network, and radio bridge circuits cooperating between the live radios and the wide area network. A number of relay radios is determined by determining the mean transmission length for the tactical training event. The duration of peak performance and the expected number of transmissions for the tactical training event are determined. The number of radios for the traffic capacity is calculated, which incorporates a QoS and a spare capacity.