RSS doesn’t natively support “subfeeds” in the way you're thinking...each feed is typically a standalone XML file with its own list of items. If you want multiple podcasts under one main feed, you could publish them all in a single RSS, but that may confuse podcast players and listeners.

A more practical option might be to create a unified feed that includes both shows and maintain separate feeds for each. That way, users can subscribe how they prefer. Some apps also support tags or categories within a feed, but support is spotty.