Randomize Material

Hi guys, I have a scene (screenshots below) and I want to randomize the lights on the tall buildings, The scene is entirely one mesh with multiple materials applied… For the tall buildings the UV map is tiled vertically and slightly horizontally…

My question is can I use a masking method to hide random portions of each material, without it tiling like the rest of the other material being used… Heres what I have…

The material currently setup

And the scene in question

Unsure if I’ve explained myself correctly lol, but hopefully you get the jist of it…

Thanks!!