Restricting sendmail

Hello, I've searched alot in the documents, sorry if I missed anything, BUT MY QUESTION IS: I want to restrict Unix/Linux System user such as XYZ of using sendmail to certain domains: in example: xyz.com xyt.com ztq.com and have it rejected if he tried to use other domains as sender Somewhat

Postfix Bug, virtual transport

e.com ___ and sometransport.example.com is a transport pipe it will work properly Best Kianoush