remove duplicate stories (or group them!?)

I noticed that some publishers post the same article in more than one feed.

E.g. if you subscribe to feeds from with the topics ‘development’-feed and ‘security’-feed you will get some articles in both feeds (some stories are exactly identical).

It would be convenient to see those stories only once.
Or maybe at least group them?
Or mark all of them as read when one is marked as read!?

I am not sure what would be the best way to handle this situation but I know I am annoyed about the fact that I have to handle the same story more than once.

Any ideas?