Mail: Select SMTP server automatically on addressee I have two SMTP servers configured in Mail. One for school, and one for my private email. I would like that Mail automatically picks the one for school if I'm sending an email to someone of my school. This means: any email address of someone of my university ends in @ugent.be. So if I write an email to xyz@ugent.be, I want mail to pick my UGent SMTP server. In all other cases, I want to use my gmail SMTP server configuration.

Is this possible? If not, are there any applications that support this feature?

(Some people on the university are very strict and won't reply unless you sent the email from your university email address. And I like it separated nicely as well.)
The automatic domain selection in Mail based on the address is not possible but....

There is a setting in Mail, send from the account of the selected mail box. 



Means, if you create or reply to emails while in the Mailbox of the University it will use that account. 

However, if you create reply from your other account it will use that one. 

So all you have to do with your 2 accounts is to make sure to use the right account when creating or replying.

Additionally you can use the "Mark addresses not ending with ....@ugent.be

Show email addresses that don’t end in a specified domain in red, to help prevent you from sending messages to unintended recipients.