I am running a website that needs to send mail. I use Office365 for normal users mailboxes. I want to be able to use the local servers SMTP to send mail from the website so that DKIM keys may be used. It seems to work as long as the "to" address isn't the same domain, otherwise the mail server realizes that the domain is hosted locally and tries to deliver locally but there is no such mailbox... If it instead looked up the MX record it would have sent to Office365 servers where the mailbox would be valid. Is there any way to make it work like this?