RSS plugin

Hi All,
I’m looking for a plugin that prevents duplicate post titles.

When I say prevents, I mean it does not publish the page if the title already exists. I have RSS feeds running, and I get duplicate content, so the plugin needs to work automatically.

I’ve found a lot of plugins that ‘alert’ You of a duplicate title, but none that prevent publishing and key, prevent publishing when the post is from a feed.

Any suggestions very welcome.

Simon