Can you Filter tweets by content or characters or adding to a category?

How can someone follow my tweets by the api url that posted it and not all tweets to that account? In other words how can you filter your tweets so that you follow only the ones that contain certain characters. Is it possible to put a tweet in a category so only those tweets from that user is followed?

http://informationalwikigroup.info

http://twitter.com/iwikig

Where each post can comes from a different page and there for one might filter out tweets from all pages that he or she doesn't want and only those urls (pages) that he or she does want.