I don't think there really needs to be any other groups.
Being a lowly skrublord, I don't know the system by which the PandemicPanda site system is set up. However, there's surely some things not even the TTV cast can overwrite about the code of the site, so such limitations have to be worked around.
That being said, having only a Master group is probably the best way to keep people active and around that actually want to be, like meee. c: