This pipe allows you to set up a Google Spreadsheet of regular expressions (or just short search terms) to match within a feed or an OPML list of feeds. Supply the URL of either an OPML feed or a straight feed. Look at the examples given to see the format that Google takes for either. Swap out your own Google Reader identifier and the label name that you are sharing to have it retrieve yours.
Pipe Web Address: http://pipes.yahoo.com/esjay/custom_alert_feeds