Pre-Rendered Exterior Cube Maps Outside Windows -- How to make visibility one per window

To speed up my tour, I’ve pre-rendered a cube map for the environment outside each window of a home.
I want to be able to have something like visibility culling per-window, so that you can only see one of these cubic maps out a window – (not seeing the geometry for a window next to it or near to it.
How can I achieve this?
To take this concept further, assume I would want to create a wall of 10 windows, each window containing an entirely different world – and even though the windows are right beside one another, have no interaction with one another. ‘port-holes to different realms’
I thought I would be able to make some sort of a masking volume to fill a window, and assign an object/level/group of objects to it.