Resolved Depth masking in deffered problem

Solved, edit below.

Hi, I'm creating a building system for my game and I started thinking about placing windows and doors on the walls. And here is the issue, I tried depth masking but it doesn't work for 2500< render queues in Deferred so I lose the shadows and I can't let that happen.

I get this with render queues above 2500:

If the render queue is below or equal to 2500, everything renders normally as before applying any shaders.

And the shader code is:

Code (CSharp):

1. SubShader{
2.         // Render the mask after regular geometry, but before masked geometry and
3.         // transparent things.
4.  
5.         Tags {"Queue" = "Geometry+1" }
6.  
7.         // Don't draw in the RGBA channels; just the depth buffer
8.  
9.         ColorMask 0
10.         ZWrite On
11.  
12.         // Do nothing specific in the pass:
13.  
14.         Pass {}
15.     }

What are the alternatives to this, possibly in shaders? The last option I have is CSG subtract but this would screw my UV and vertices caching etc.
Thanks in advance!
Nick

EDITED:
Well, now I learned a few things about shading and now I know why this approach wouldn't work. If anyone ever had the same problem - in built-in pipeline probably the easiest solution to this is to use clip() in the surface shader and add #pragma addshadow