The Forward option, which you can find in the Email Control Panel -> Accounts menu-> Edit account, allows you to automatically forward the incoming messages to another address: in the page which appears you simply need to select the “Forward Account to:” option and enter the destination email address of the forward (you can specify up to a maximum of 5 addresses, separated by the ‘,’ symbol).

If you also wish to receive a copy of the incoming messages in the domain account, besides indicating the forward addresses, you need to select the ‘Enable Save Copy and Alias' option.

Deselect this option to forward all the incoming messages without saving a copy in the email account.