You can select any IP Radio stream from the web and play it in on any Zone or many zones, but if your looking for it to be synced together this is not possible you would have to use a audio matrix switcher to use a single zone as a master and then select which additional zones you want to connect to it.
The example diagram is a 8 x 8 Audio matrix switcher any source can be connected with any output zone.
Link:
http://xlobby.com/news/wp-content/uploads/2012/03/95-2035-multiple-Amp-Setup1.jpg