How do I find custom 3dtext shaders?

I am working on a text-heavy game in unity and everything is going as smooth as butter, idea I would love to see (would open up allot of oppertunities) is to mask the 3d text so that when one overlaps the other the overlapping text will shade black (as opposed to white), so it stays readable.

My best guess is doing this with a shader, which is a very unfriendly field for me. I figured maybe someone on here knows where to buy/download/etc. a think like this or if anyone can write this up in a few minutes. It would mean a great deal to me and my game.

I know that, if nobody can help me, I'll be forced to learn how to write my own shaders like a boss, so there is no reason to repeat this sentiment. If any of you see any impending problems in the tech I'm describing please do address.

For the people that do actually help; you have my enormous gratitude.

Hendrik