If creating or modifying an O365 distribution list or group, and you need to add a non-Berkel email address, do the following:


1.  From O365 Portal, assuming the dist list/group already exists, click Users

2.  Under Users, click Contacts

3.  Create New Contact

4.  Enter the pertinent info and external user's email address

5.  Now, return to Groups > Groups and select Edit inside the desired dist list/group 

6.  You can now search for the external email since it was entered as an O365 contact