The 3 roles you can assign to a Practitioner are;
Chain Manager - Has full access to all settings in the chain
Setting Manager - Has full access to a specific setting
Practitioner - Has limited access to a specific group in a setting
A Setting Manager can manage more than one setting at a time, as long as they have been assigned to each setting;
A Practitioner can be added to as many groups in one setting;
Note: When using the App, make sure the manager/practitioner is assigned to the same group as the device.