Okay I understand, you want to pull a feed and re-populate it's contents on your WordPress web site on say an hourly or daily basis?
Once the content is replicated into your WordPress blog, PowerPress will pick it up. The problem is PowerPress was not built to "aggregate data" from other feeds. There are other WordPress plugins that facilitate that function.
The trick will be finding an aggregating feed pulling plugin that also imports the enclosure data from the RSS feed. Either way, this is something that you can hire us for consulting you with. This is not something that's of the norm for an a podcaster but is a common task we address for our enterprise clients. Use our contact form www.blubrry.com/contact.php
and indicate that you would like to hire us for consulting regarding "aggregating podcast content from other web sites via RSS feeds".
If you plan on pulling more than 1 feed on a daily/hourly basis, that's exactly what www.blubrry.com
does in the form of a directory and that infrastructure we provide as a service called the RawVoice Generator
and is available through our corporate site www.rawvoice.com