Adding more races?

I just want to say now that I don't know how modding works, I don't know the limitations of modding and I don't know the process... That said, I was just wondering if it would be possible to add races to the EE games, I'm thinking like, maybe if someone created rules for a gnoll or something and then used the gnoll graphics to represent that character in-game.

even if this is possible, it would probably only work for IWDEE because in BGEE1/2 it would be much harder to implement due to all the PC interactions.