How can I build a view of feed items of a particular feed?

I have successfully created several feeds (e.g. health, cars, politics, etc). What I want to do is create a view that pulls all the items (or some views-related subset) of items from one of these feeds. Something similar to what can be done by taxonomy and views (i.e. pull all nodes that are tagged with gym). I keep reading the documentation, but I can't seem to figure out how to do it. I saw the whole Parent Feed argument thing, but saw no documentation on how to use it. I'd like to create blocks similar to what can be done with the aggregator module that comes with Core, which automatically creates a list of items for each feed.
Any help would be great.