This seems to apply here as well, so I'll make my rare repetition of comment:
There are quite a number of all-girls colleges, both in Japan and still in the US.
Examples:
USA -
http://www.womenscolleges.org/colleges/byname
Japan -
http://en.wikipedia.org/wiki/List_of...leges_in_Japan
As you can see... there's an armful.
And the manga and anime both explicitly state that all 4 of the seniors are attending an all-girl's college that caught Mugi's eye early in the process.
Storywise and dramatically... I think it'd be *interesting* to follow the gang as they grow up, enter relationships, and how that might impact their musical aspirations. But there's too much of a component of otaku fantasyland in the readership for this route to be likely.
Frankly, I'd be happy just to see the collection of stories end with them going through college, getting a professional contract and fade out on the peak of their careers. Of course, I'd also like a Rock Band package of their characters and their tunes but I don't see any flying pigs around. __________________