Let's try and go through the program option as I outlined that you could add in the category editor so we can show you how this works.
You asked me if you could link a feed url into a product and gave an example link, here is one: http://www.godcast.org/categories/theLivingWord/rss.xml
Now lets explain this in more detail
In the Admin section of the software you can setup 6 extra fields and name them as you choose. This is the extra field I was referring to of the six and you can name one say external rss feed whatever. When you add the item, you can place a url link in there.
I think the best example I can give would be to show you a visual example on my own test site http://www.reeftalk.com/classifieds/...hp?product=116
I hope that shows you what you want to see as this is how I interpret what your saying here that you want. If not let me know