Layer Metahuman Materials

Hi everyone! I’m working with metahumans and I was wondering if there was a way to layer materials on top of what’s already there. For example, I’d like to add, say, a tattoo on top of the skin. I don’t want to mess with the original skin material (I know I could export that out and edit it) because the tattoo would be modular in game (you could swap it out with another one). I have other materials in the game that I don’t want to overwrite, so I was wondering if I could overlay the tattoo image over the skin or something?

Any suggestions?

Thanks in advance!