Methods, systems, and devices for wireless communications are described. In some examples, a base station may transmit, to a secondary user equipment (UE), a first grant to conditionally transmit one or more data messages over a first set of resources upon completion of a detection procedure. The detection procedure may include monitoring a second set of resources for over-the-air (OTA) signals transmitted by a primary UE pursuant to a second grant, where the first set of resources at least partially overlaps the second set of resources. The UE may monitor for the OTA signals from the primary UE, determine that one or more conditions for transmission of the one or more data messages have been satisfied, and transmit the one or more data messages over the first set of resources.