App that filters out posts that are popular in a specific chamber

I'm sick of seeing the same threads in r/kingcobrajfs and r/offmychest. I want an app that filters out any posts with the same caption as anything I already seen in another subreddit.<br><br>The way this app would work is that you tell it what chambers you want to compare. Then it will show you a list of posts from a chamber and it will grey out or otherwise indicate which ones are in another subreddit. Then you can tap it to go to the post.