For use in a wireless computer network having a radio relay capable of transmitting messages, a system and method, operable with the radio relay, for selectively repeating a unicast message received from a source end-station only upon some indication that a destination end-station has not received the message. The system includes: (1) a transceiver that receives the unicast message from the source end-station and (2) control circuitry, coupled to the transceiver, that determines whether the destination end-station has received the unicast message and causes the transceiver to refrain from repeating the unicast message if the destination end-station has received the unicast message, the radio relay thereby freed from repeating already-received unicast messages.