With Email Forwarding, you can forward emails to multiple other email addresses (This does not delete the server copy of your incoming emails)
Go to: https://<IP Address>:8090/email/emailForwarding
Note: Make sure to create at least one email account, otherwise you can not create email forwarder.
First select domain.
On second option select the source email, emails from this will be forwarded to your destination.
Finally, enter your destination email.
You can forward to more than 1 emails.
To stop forwarding to certain email just delete the entry and server will stop forwarding your emails.