Is there a way to texture just a certain part of a brush face and not have it as just one texture?
Take out the material editing tool (The box with multiple textures on it, on the left toolbar), select a texture, and right click on a face.
No, I mean is it possible to have two different textures on one face?
Clip the brush in half and texture each face differently.
One texture per face. Clip the brush to apply more than one texture to a viewable area.
You can blend 2 textures on a displacement.