Our 5 and ups practice at the same time. They group though as just 5s and then 7 and up. we have no 6s.
They tend to hang out with their groups on breaks at parties, etc. but they also tend to be of similar ages.
This is sort of what I'm asking. All of our optionals train at the same time, but they tend to divide along level lines outside the gym, not as one group of optionals, like they did before.