Departments that you do not need at the moment can be moved to a different location in the weekly schedule or they can be completely hidden.
In the category "Schedules" you have the option to change these settings. In the list view as well as the calendar view you have a list of all departments on the left hand side.
While moving the mouse cursor over the departments in the list a small hand symbol appears. Here you can drag&drop a department to a different location in the list. The order in the list view will change immediately.
Simply click on the department in the list that you want to hide in the weekly schedule.