I am setting up a Mailenable server for my domain example.com. I am setting up 10 users in the post office. I want to set up the below use case,
1. Receive all emails from the outside world to my domain.
2. I want to restrict five certain email IDs on the server to send emails outside example.com. I mean I want them to receive emails from anywhere but they should not be able to send emails outside my domain
Would like to know how to set this up.