Are you sure about that, Thom? It's not documented on the CREATE LOGIN page, and I just successfully ran this command on a SQL Server 2014 server:
CREATE LOGIN [DomainName\GroupName] FROM WINDOWS WITH DEFAULT_DATABASE = John
You may be confusing this with default schemas not being able to be assigned to users mapped to logins that are Windows groups.
John
Yep, sorry! You're right. Clearly brain not engaged yet!
There are no individual logins. Individual Logins are added to AD groups. These groups are added as server principals.