Assinging Priorities to Telemetry ports

Is there any option to override the companion computer? I have been using using a companion computer connected over TELEM2 port and just as a safety feature would like to intervene from the main gcs at times. How does Ardupilot handle conflicting mavlink messages like for example if in guided mode the main GCS instructs to move towards point A and the companion computer instructs to move towards point B. Has anyone tried something similar before?

Who ever sent the last message wins.

Thanks for the clarification @iampete, is there any way I can make my quad ignore the messages from the companion pc in realtime.

I don’t know of a good way, I haven’t done a huge amount with companion computers so there might be something, of course you could just turn off that serial port.