I'm taking this up with the development team.
The AD Group management functionality still exists in the beta version.
If you go to "Options", then click the "Administration" tab, then click on the "User Administration" button, you should then see an "Add Active Directory Group" button in the upper right.
If you don't see that button then DPA is probably not configured to use Active Directory. See the following article to check your setup: Ignite user authentication and permissions using Active Directory - Confio Article 1640
Thank you. That link had the info I needed to make it work. The AD Group button is showing up now. Thanks again.