In the staff setup page, you can define your staff member's specific hours if they are different from your regular operating hours.
If they are not in a particular location on any day, you can define their hours as closed for the day.
Staff can also 'filter' their hours from directly within the 'Diary'.
In the diary select the staff from the left side of screen, if not visible you will not to display the sidebar by clicking the arrow as shown below.
A clock icon will now appear next to each date and this feature will allow the staff to 'filter' their hours.