I need to have a split domain setup on Postfix. This is [possible with Zimbra](http://wiki.zimbra.com/wiki/Split_Domain) which uses Postfix as described here:

> 
> If delivering to a single secondary mail system, configure a catchall on the domain to deliver mail to a secondary mail transport if users for the same domain reside on the second system.
> 
> 
> 
> ```
>   zmpov cd example.com
>   zmprov md example.com zimbraMailCatchAllAddress @example.com zimbraMailCatchAllForwardingAddress @example.com zimbraMailTransport smtp:mail.example.com:25
> 
> ```
> 
> Mail for Zimbra recipients on the primary system to @example.com will be delivered Zimbra mailboxes. Any address that does not exist on the Zimbra system will be routed to the secondary mail transport. This configuration will likely work with 4.5.x, but it has not been tested.
> 
> 
> 

How can I achieve this in Postfix?