Does Zimbra have support for event sinks (or some equivalent)?

We have a custom built event sink (ISMTPOnArrival_OnArrival) that automatically handles what is sometimes called "plus addressing" with the added functionality that it auto creates subfolders in the user's mailbox with the '+' structure and filters the messages to those folders. For example, a message sent to would end up in

and totally skip my inbox (and the folders are created if they dont already exist). We use this all over the place in a variety of ways and would not be willing to lose this functionality.