For example, the minimum security prisoners are allowed more free time, whilst the normal security ones work, and the high security prisoners are locked in their cells.
This could also give the ability to have staggered meal times (which seems to be a feature that a people want) and possibly shift patterns for guards.
Forgive the crudely edited screenshot, but this shows the sort of thing that I was thinking:
Apologies if such an idea has been posted before, I don't really want to look through 30+ pages...



