Shader Stencil - hide in contact with shader stencil

when a "shader stencil" enters another "shader stencil" of the object is hidden

This will help me to cut part of the objects, creating an effect which disappears in cutout shape

for example:

//////////////////////////////////////

I read the guide, but can not find how to do it correctly. http://docs.unity3d.com/Documentation/Components/SL-Stencil.html