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.
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.