The Issue: For several years in the Podcast realm, its been common to have an episode of Podcast A include all of an episode of Podcast B in their feed, usually with an introduction. Which is usually intended to get you to subscribe to Podcast B, if you aren't already. However, if you are already subscribed to both Podcast A and B, you wind up getting a double download of essentially the same episode.
Suggestion: To fix this issue, I suggest a borrow tag to the RSS feed, it would work something like this:
<borrow><url of episode></borrow>
In practice it may look something like this:
The above example would indicate that the episode of my own show was included entirely inside the episode of another show.