1. In default mode employees can see only members of the their department.
Employee's Team View of department
2. Absences can also be shared between all employees regardless of their departments. This can be done by selecting option shown below in General Setting and pressing Save changes button.
Option to share absence between employees selected screenshot
This how it will look like for the same employee on the Team View
Team View when absences are shared between all employees
3. Absences can also be hidden from everyone but admin users. Using this option In General Setting.Once it is chosen press Save changes button. In this case employee will only be able to access personal Calendar and Team View for entire company will be visible for admin users only.  
Option to hide absence for non-admin users selected screenshot
4. Another option is open Team View for admin users to see entire company and for managers and secondary supervisor to their departments only. The rest of the users will be able access personal Calendar only. This feature can also be selected in General Settings and once box is ticked Save changes button saves the changes.
Option to hide absence for non-supervisors selected screenshot