Rio Receiver & Rio Central

It is possible to have my rio receiver at work on my work network connect to my rio central on my home network?

Not really. For a start someone would have to write a proxy for the Receiver discovery protocol (pseudo-SSDP), so the Receiver would know to contact your home IP address for music. Then you'd have to leave the ports in question wide open on your home router. And even if you'd done all that, playback would still be really flaky, as there isn't a huge amount of buffering in the Receiver, and a lot of the UI does network stuff synchronously (blocking until replied) under the assumption that its server isn't very far away.

You'd be much better off arranging for a complete copy of your collection to exist at work, perhaps on a USB hard drive, and then running Receiver server software on your work PC.

Peter