I'm not too sure either. They had cliques, but they weren't exactly on the best of terms as the current line-up is.
Like there was the Reina and Gaki beef for a while, and Sayu and Reina never really got close until Suugaku Gakuen.
I mean like at Koharu's graduation, JunJun was like "let's eat together soon". Colourful Era girls hang with each other much more though from what I can guess.