Manually. When you set up AD auth, you have to manually select the groups to import into the device (or you can select all of them.) Once you've done this, any new groups created have to be manually imported. From the new rule window, if you change the rule to "based on group membership" and click Update, you'll see a Groups button, click that and it'll open a window showing you the groups that have already been imported. if you click on the search button, it will open the group catalog. This will list all of the groups that it sees in your AD. (so if you do this immediately after group creation, they might not show up due to replication delays, etc). You can now choose any or all groups to add and click Add Selected. I hope this answers your question.
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