It is possible to play the files under a certain view scheme as radio:
right-click the view scheme (in the tree) > send to > play (optional zone name) > play as radio
You just need to create a view scheme that excludes the podcast files.
I'd be interested to see this tested. I suspect that this uses the contents of the View Scheme as a seed, but does not limit the radio exclusively to those contents (eg Podcasts could still get picked, though it'd probably be less likely). Perhaps Matt could comment.
On another semi-related note...
I've been using the Radio function extremely heavily for the past few weeks since it was implemented. My wife loves it, as I've attested to before, and it was also a pretty big hit with some of our other good friends (who have a passing understanding of MC). However...
They've both asked again and again for an
easier way to start the radio up in seeded mode. Starting it "unseeded" is certainly easy. However, as it is now, you have to dig down into the Send To menu to start it up in Seeded mode This is a bit too much for some of my users, particularly because I have three Zones configured and they don't know which one to use intuitively.
I'd
really like to see
Play As Radio promoted to the top level Right-Click menu just under
Play and
Add to Playing Now. As is, I always have to show them, and then it's in the "remembered commands list" (so they just use it there), and then they forget how to drill down to Send To to find it again the next time they want it. So they ask me again, complain that it is hard to find... Rinse, wash, repeat.