I'm not aware of a specific mechanism for SMBus slaves to communicate with each other. Perhaps you're referring to the "Host Notify Protocol" which allows a slave to send messages back to the master. The purpose of that protocol is to allow a slave to send time critical messages back to the master without having to wait to be polled. I guess that protocol could be used in a system to allow slaves to communicate with each other, but that was not the original intent of that command.
The SMBus/PMBus component datasheet ( http://www.cypress.com/?docID=39795) describes which protocols the component supports on page 25. Host Notify Protocol is not supported at this time.
I concur, I misinterpreted the language "a slave can take on the role of a master" as
necessry condition to characterize a slave device's functionality.
Still waiting for release of a master module in Designer.