I'm trialling XEAMS at the moment with a view to buy enterprise (for multithreaded send) purely as an SMTP relay to manage on premise devices sending email.

So far so good, however I do have some devices (printers) that I wish to only send email to a list of ~10 internal domains.

I'm not sure how to achieve this with XEAMS, I haven't found any way to enforce a restriction on recipient.

I'm toying with the idea of having a relay for outbound and a relay for inbound configured with different smart hosts where one can send email externally and the other (M365 smtp inbound option 2) cannot.

Is there a more elegant solution for this than adding more XEAMS servers?