Trim intersecting surfaces

Hello,

I am having issues With trimming surfaces With other surfaces.
I have wall surfaces that are intersecting at the corners, where I wan to cut the surfaces With each other, which I can't figure out.

I also have a roof surface, which is not Attached to the walls yet.

I want to join all the surfaces together; walls, floor, roof, and create a closed geometry, so that I can test it for Acoustics in pachyderm.

The surfaces are grouped in a blue Box in the grasshopper file. You probably have to zoom a little but out in an empty rhino file to find the geometry

Hoping someone has a solution :)

Best Regard,

Gestur