Hide objects behind invisible objects (Hololens 2)

Hi,

I need to hide objects behind invisible objects.

Indeed, I must display virtual cars that can move behind a building.
The buildings are mehes (FBX) superimposed on reality, but which are not displayed. They only serve as a mask.
(I can’t use spatial mapping because the buildings must be those coming from an FBX).

Is it possible ? How?

Regards,