mail from domain to domain on same server (second domain mail is hosted on different server)

Hi all, I have situation where user have only web on my cpanel server (mail is hosted at different hoster) so when users on my server sends mail to this domain, e-mails are not sent. How to setup account or user (that have only web hosting) in server that e-mail massages sent from other users on same server are sent to that address where mail is hosted at different hosting?