My iOS app doesn't necessarily aggregate them into one area, but it highlights them in the main list. I believe that the Show HN posts are actually the best part of this community, so I wanted to visually distinguish and highlight those within the app. It's free, so you can check it out if you have an iPhone.

https://itunes.apple.com/us/app/news-yc/id592893508?mt=8

ShowHN Highlighting screenshot:

http://a5.mzstatic.com/us/r30/Purple/v4/8e/8e/cc/8e8ecc01-c1...