Projecting a texture

Hey guys,

So I have a texture I want to project onto a building, like a Decal of sorts. But I was trying to make this dynamic depending on some other variables in the game.

I was trying to use a projector to show it up similar to the blob shadow projector. I setup an empty gameobject and added a projector and the texture I was testing out with and it projected on the entire map. Looking around I figured I needed to clamp the texture and that didn't fix the issue as it projected the texture 100% across the terrain and everything (even when the projector was aimed and situationed properly). I tested out the shadow blob projector and that worked fine so I tried to manipulate that one but I couldn't get it to work.

I guess the main question is, how can I setup a projector to show a "spotlight" effect of a texture onto another texture? (with not actual spotlight involved)

Thanks!