This is what people call a split domain, and you can do it (there is an article about it).
However I would avoid it at all costs, if you have another solution for what you want to achieve, because this is looking for troubles.
You have to be careful with SPF records, that they declare both servers valid for sending mails for the domain. If you use DKIM on the domain, the DKIM config should be the same for both, etc...
TLDR; It's possible but discouraged.
Sébastien Riccio
System & Network Admin
https://swisscenter.com