Is it possible to add a Shared Mailbox to a Distribution List.
Add-DistributionGroupMember -Identity 'DL Name' -Member 'Shared Mailbox email' -Server $ADServer -Credential $mycreds -ErrorAction SilentlyContinue
This is a general purpose forum for discussions about the overall community. I would recommend reposting this in one of the forum in this network that is focused on Exchange and/or Office Groups.
I'm moving this message to the Exchange community for better visibility.