it is really hard to managing groups for users. some of groups must be normal distribution group and some of them can be dynamic. Basically, we use dynamic groups for department distribution groups and branch distribution groups.
The best way of explaining dynamic group is giving examples.
For example you have two offices, Sydney and Melbourne, and each office has 50 users. When a user joins to team or leaves, you have to add or remove user groups. If you create a dynamic groups which has condition that is “If State is Sydney or Melbourne”, a new user will be added to a dynamic distribution group automatically according to state on its Active Directory account.
Open Microsoft Exchange Server management Console and go to
Microsoft Exchange On-Premises>
On Actions panel, choose “New Dynamic Distribution Group”
type Name and Alias what you want
Choose recipient Type, I will choose All recipient types and click next
select the box named “Recipient is in state or province” and than “Specified” section in the Step 2 panel
and write your state name, Melbourne and click add
click OK and Next
when you click “New” a new dynamic group that has members who in Melbourne will be created.