If you would like your users to be able to add and remove users from the groups they manage, then yes. You will need to install the ADMINPAK.MSI from the server c:\Windows\System32. You will also need to enable the management in the group properties themselves. On the Managed By tab, you need to click Change and then select the user. You also need to check Manager can update membership list. It would also be a good practice to create a custom task pad that will allow them to only add and remove user accounts from there group. This ability should only be for users in the OU that contains the group.