Is it possible to use more than one foundation type on the same plan? the house I'm building has a walkout basement with 8" stem walls, but also has a main floor room that I'd like to have a post and beam foundation below it, so it's possible to exit the basement below this room and walk underneath it. I can't seem to specify a separate foundation type for just one room. I've attached a photo of what I'm trying to do as an example.