Update podcasts on iPad. Possible?

Here's the scenario: Going on a trip and taking iPad, no computer. Prior to heading out, I will update podcasts to listen to on the plane. When ready to head home, want to update podcasts again for the trip back. I can't seem to find a way to do this (looking for something that will update in one fell swoop -- like the "refresh" in my iTunes). I guess I could go into the iTunes store and search them out one by one, but that does not seem like a very managable way. Does anyone have any suggestions?

Thanks in advance for your help!