rss help

Wonder if anybody could help, I am looking for a plug-in which would give me a second rss feed on my site, this rss feed would be populated with only posts that I select.

So in effect when I write a new post on my site I would have a check box and if ticked the post would be placed into the second rss feed.

Been looking through all of the rss plug-ins and can not see one which would do this as of yet, if anybody has any suggestions it would be greatly appreciated.