Back to the question at hand. I think if you were getting a straight up legitimate massage, a couples massage would work well. There’s probably a few places that would do that. I don’t know what the capacity is at The Prime Massage for a couples oil massages, but there was a recent report about an excellent couples Thai massage (where you wear a PJs type outfit and are not nude for the massage). Prime would be a highly unlikely place to get afters, and essentially impossible with two therapists in the room.
However, if you are looking for a massage with afters, I think that you are far more likely to get satisfactory afters if you have your massages in separate rooms. The massage guys may not be shy with you, but there is a significant risk that they may be too shy to perform to your satisfaction with one of their colleagues in the room.