Can you run MAVROS and QGroundControl at the same time, over the same radio?

I have a Vicon system running on a companion computer and a pixhawk autopilot, I would like to have MAVROS transmit MOCAP messages through the radio to the UAS, while still using QGroundControl for arming and in-flight inspection of telemetry. Is this possible using a single radio?

Yes that’s possible. If you’re connecting through mavros on the companion computer, you can use the gcs_url in the mavros launch file.
Alternatively, you can use mavproxy to split a mavlink stream by having one master and multiple UDP outputs.