Our email is relayed through mailgun using the account email@example.com. The ‘on behalf’ for @domain.com is fine.
One or two users need to send from @domainsupport.com. Those have the ‘on behalf’ problem.
Both domains are verified.
Is there a way to have the on-behalf work for domainsupport.com under the configuration authenticating as firstname.lastname@example.org?
If we could control the 'on behalf' across one of the two domains that would be beneficial.