You can create any number of groups through which to categorise your users. This enables you to separate your users and diary events according to these groups. If, for example, you have users spread across the country, you can set up user groups that are location specific in order to see on the diary only events that are related to that specific group.
In order to set up your user groups, first, go to your system settings. Scroll down to the 'Users' section and select 'User groups'. From here, you can name your user group using the dialogue box on the left and save it using 'Add user group'. You can edit or delete these once saved on the right or changing the order they will appear in dropdowns by dragging and dropping them.