Edit: Nevermind - this KB says Send As Distribution and Security groups won't work in Outlook 2011/2016 on mac: ------- In Outlook 2016 Mac, you can go into Preferences > Accounts under personal settings > Advanced Button (bottom right) for Account you wish to edit > Delegates Tab at top > Add account under People I am a delegate for > search for distribution list/group/person. The from field should show up after setup on replies and new messages. I was able to test successfully with a shared mailbox, but not a distribution list; not sure if it's because something isn't working on my end or not. We're O365 users as well, but I tested on my personal Mac. Hope this helps! I do not have an answer for you but I do see a potential pitfall. This is from experience with users on Exchange.

I am not a supporter of shared local user Distribution Groups. A user having their own Distribution Group is great. Sharing it not so much.

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Example: A user 'Jill' creates a local distribution group and sends it to several associates (as you are proposing). Let's say that in the Distribution Group there is a user 'John Doe'.

John leaves the company for whatever reason. Jill knows so she deletes him from her group. She is very meticulous so she sends an email to the group informing them John is gone and should be removed from the group.

Some of the users do so, others do not. You have been notified and have marked him as inactive and removed or shut of his email account. One of the users who did not remove him sends a email to the Group.

They get an error message saying that the email to John Doe can not be delivered. They open a helpdesk ticket. Days later another user does the same thing.

And it may happen many times depending on how far this had been shared. Because it is not a server based distribution group you do not have control over members and may not even know who all the group users are. Result, Headache for IT. Users grumble that IT is slacking on the job, etc. Edit: Nevermind - this KB says Send As Distribution and Security groups won't work in Outlook 2011/2016 on mac: ------- In Outlook 2016 Mac, you can go into Preferences > Accounts under personal settings > Advanced Button (bottom right) for Account you wish to edit > Delegates Tab at top > Add account under People I am a delegate for > search for distribution list/group/person.

The from field should show up after setup on replies and new messages. I was able to test successfully with a shared mailbox, but not a distribution list; not sure if it's because something isn't working on my end or not. We're O365 users as well, but I tested on my personal Mac.

Hope this helps!