I've got the full deal package with grouper and such. Is there a way to generate a feed from my main feed, based on keywords?

i LOVE how you're able to take your own feed and display it by keywords. But is there a way to generate a feed based on keywords? I suppose scrape it, in a way?

The reason I'm asking is I want to be able to give out RSS widgets to the public based on certain keywords so they can then utilize those on their own websites. So someone might find it useful to have an RSS from us about the town of Oceanside, while another would want the subject of Lincoln City, for example.

The only option I see now is to do this by hand: create a separate feed for each keyword.

Or if there was an RSS widget that filtered a feed by keyword....but i haven't found one.