I don't think there is an overly scalable way to tackle this since I cannot find any logging of account enable/disables (in Cloud). I'm happy to be proven wrong though!
If you're only looking to run this type of report once, It might be worth while getting a list of all currently active users within your community using the Jive REST API v3.14 → Person service ), then removing the duplicates against the membership of your AD group, then adding the left over users into the AD group. Note: You would have to have a unique identifier between Community profiles and Active Directory.
If you need to run this report ongoing, I would process the above first, then using the same person service you could look for accounts modified since the last mass addition by using date queries:
Then again removing the duplicates from the current AD group members and adding the left over users.
Not ideal, but hope that helps.