To group users automatically, use the dynamic groups function. A dynamic group includes all contacts that meet your pre-selected criteria at the time a message is sent.
Creating a Dynamic Group
In Users & Groups go to Groups and press the 'Create Dynamic Groups' button. The following screen shows a list of available dynamic group categories, with number of groups per category listed to the right.
To create a dynamic group, click the Create button next to the appropriate category. The Refresh button creates new dynamic groups for new entries in the category (such as if you have added year levels, rooms, classes etc since creating groups for this category).
