Hi, I was wondering if anybody could help me out with something.

Is there any way possible to perhaps take a patch like for example the legions characters/creature models and add them as an extra instead of them replacing the current ones?

Basically what I'm asking is to add them as new stuff instead of replacing but I have no idea how and if anybody could help me do that or give me a guide/tutorial on how to do it.

Thanks for your time.

EDIT: If you'd like or need more info of what I'm asking please feel free to ask.