the room every source lives in

Kuules Scene is the room. Every Beacon in the session gets early reflections and a tail from the same walls, at the right delay for where it stands.

One room, not one per track. Change the room once and every source hears it.
Each Beacon's reflections come from where its sound would actually hit the room.
One reverb for the whole scene, so sources sit in the same air.
Half the CPU when the tail is the cost.
Open the sky and the room's tail gives way to scatter — the ground, the trees, the sides of buildings: short, dull, falling away with the source. The same law as Kuules Weather, so a weather scene in a Scene room agrees with it.