Let me guess. Do you have Transparent CanCollide walls to keep the Player from walking through the MeshPart?
You can make the Transparent Parts slightly smaller and hide them inside the walls.
You can make the Transparent Parts not transparent and put a BlockMesh in them. Make the Scale of the BlockMesh really tiny, (like .001,.001,.001) and it will make the camera ‘hit’ the surface of the wall Part. If the tiny Mesh rectangle is visible in a door or window you can just use the Offset of the BlockMesh to move it off to the side.