Before I get started this is not referring to standard Distribution Groups, this email refers to the groups that can be created in the newer version of Office 365 that allow a “Lync-esque” conversation feature but with added functionality, such as reviewing previous messages when added at a later date.
In most environments this would be a great feature, workplace and alike, however in environments like schools it can lead to some administrative troubles as there is no, current, way to administrate the groups once created as they are hidden to the admin unless viewed within the mailbox/OWA of the user doing the creating.
In this particular case these groups needed to be, A: removed manually, and B: disabled from future creation.
First you have to log in to the exchange mailbox via PowerShell, so have your admin credentials ready, once you are in and are ready to make changes, this is the command to run;
Set-OwaMailboxPolicy -Identity <strong>DOMAIN.LOCAL</strong>\OwaMailboxPolicy-Default -GroupCreationEnabled $false
You can create a new policy and apply the above change to it, then set that policy as the default for your users/groups.
Please see this article for a much more in-depth overview of the feature and how to disable or utilize it.
If you have any questions please email me.