Fine-grained Scheduling Permissions

Not really sure how this would work in any sense... but here goes! It's good, obviously, that artists can't edit the official schedules, but it's been suggested that it would help them if they could create/edit their own internal milestones within their departments (e.g. the rigging department members have their own internal schedule, somewhat independent of the official schedule assigned to the various individuals). Sorry that's a bit vague, but just thought I'd put it out there as a kind of use case