Security Groups o365 automap mailbox question

Hi,

I wonder if anyone knows a way within powershell to add a a user to a security group and have it auto map the mailbox. When i add users security group with users in it to a mailbox we have to manually add the mailbox. Or just do this command seperatlly but then this gives the users direcct access to the mailbox and makes the SG irrelvent. 

Add-MailboxPermission “mailbox@mailbox.com” -User "users@mailbox.com" -AccessRights FullAccess -InheritanceType All -AutoMapping:$true
Add-RecipientPermission “mailbox@mailbox.com -Trustee "user@mailbox.com" -AccessRights SendAs