A ready-made example to start with: the drums are already in the shared room, the other tracks keep their own reverbs. Press Play and switch As delivered on and off: you hear how the room glues the drums. The graph marks where to look.
One room 4% → 23%Reverb in the mix −13.9 dB
A dot is a track, a small circle is its reverb, the big circle is the shared room: whoever is inside is in it. The closer the dots, the more the mix sounds from one room.