Question Allow specific email address to be reachable only by emails on same domain

[pierino84]

Hello,

I have set up an email which acts as a forwarder: when I send en email to it ([email protected]) this email gets forwarded to all colleagues' emails ([email protected], [email protected] etc...).
This forwarder email has no mailbox checkbox activated, and no password has been set up. The messages are forwarded correctly.
Now, I would like for this forwarder email to allow messages only from email addresses of domain1.com, so that no one from other domains than "domain1.com" can send and forward a message to everyone.
How can it be done on Plesk Onyx 17.8.11?
Thanks!