I remember years ago bus stops that were shared by more than one route having "queue this side for x/y/z" on one side and "queue this side for a/b/c" on the other... thereby splitting the queue into 2... of course that was in the days where you wasn't guarunteed to get on the first bus to come along!
Interesting, that would be very useful at certain bus stops in London where there are multiple buses that only come every 20-30 mins.