Login to Office 365
Click on the Admin icon
Click in menu on the left go to the admin center, choose exchange, Exchange admin center opens, under recipients, click on contacts
Click on “Add”
Choose “Mail Contact” from the drop down and complete all sections as shown, click “Save” if this is your first entry it will take some time to save, then additional entries will load much quicker.
Once saved it will show the contact that you just entered. Double click on the contact name. This next step is very important! Click on the “Hide from address lists” This will hide it from the Global Address book.
You can now add the new contact to the requested distribution list. Click on “Groups”
Click on “find” (magnifying glass) Enter the name of the distribution list in the search window
Double click on the requested distribution list
Distribution list appears, click on membership
You can now add the new contact to the distribution list. Click Add (+) Click “Find” (magnifying glass), enter the user name, hit enter
Click “add” name will appear in window, click ok.
Click “Save” Double click on the distribution list you just added the email to and verify the entry.