Shifts Limiting "Write" Access

Hi

We use Shifts to coordinate technicians schedules

We have about 10 Managers and Project Managers that need to see the schedule in its full capacity, this is how we forecast upcoming work...

My problem is that once the schedule is set a "few" will go in and make changes.

How can I stop this? If a make these Managers Members vs Owners they can only view their own shift not everyone else's