The administration and maintenance of Microsoft Exchange Server to ensure secure, reliable, and efficient email and collaboration services across an organization.
Currently not possible since automapping leverages auto discovery. The auto discovery piece would need the ability to expand the group ( and expand it each time it ran) and thats not part of the specification.
You can always request as a feature however
https://feedbackportal.microsoft.com/feedback/forum/89a8afa3-2e1c-ec11-b6e7-0022481f8472