Shader that remains the same transparency when overlapping, using for shadows

Hello,

I'm looking for a shader to use for the projection of shadows. Problem is when 2 shadows overlap each other the overlapping part get's darker as you can see in the image. Is there a shader that prevents the overlapping part so that it remains the same transparency?

Thanks

 

you can use stencil buffer.
For area that has been rendered by shadow,any other shadow will skip it's rendering.

Code (CSharp):

1. //use Stencil Buffer to prevent multi Blending            
2.             Stencil
3.              {
4.                 Ref 1
5.                 Comp NotEqual
6.                 Pass Replace
7.                 Fail Keep
8.                 ZFail Keep
9.                 ReadMask 1
10.                 WriteMask 1
11.             }