I would like to set up a sub-category listing all articles about a particular topic (e.g. all articles about "Hillary Clinton" or "Mitt Romney") across several different feeds.
This is kind-of like a stored search, except that I would prefer not to have to look it up manually. Rather, it would be nice if it gets bold text when a new article fits the criteria.
Is there any way to do this?
You should try RSSOwl 2 from boreal.rssowl.org. Upcoming 2.0 Milestone 6 will support what you request.