add users to multiple administrative units

explain that users can be in multiple administrative units, and provide an example.

Author: anwarmahmood1

articles/active-directory/roles/administrative-units.md

@@ -21,6 +21,8 @@ This article describes administrative units in Azure Active Directory (Azure AD)
 
 Administrative units restrict permissions in a role to any portion of your organization that you define. You could, for example, use administrative units to delegate the [Helpdesk Administrator](permissions-reference.md#helpdesk-administrator) role to regional support specialists, so they can manage users only in the region that they support.
 
+Users can be members of multiple administrative units. For example, you might add users to administrative units by geography and division; Megan Bowen might be in the "Seattle" and "Marketing" administrative units.
+
 ## Deployment scenario
 
 It can be useful to restrict administrative scope by using administrative units in organizations that are made up of independent divisions of any kind. Consider the example of a large university that's made up of many autonomous schools (School of Business, School of Engineering, and so on). Each school has a team of IT admins who control access, manage users, and set policies for their school.