Does booking passenger profile dictate upgrade priority based on their medallion status or will their companion who has higher medallion status, if booked on the same record, give them the benefit of that higher level?

Scenario is if a PM booked with a GM on the same ticket then both share the PM status. But what if the GM booked the ticket (eg on their app or logged in, as pax 1) and then added PM pax as pax 2. Would the booking be handled as a GM level or PM?