Automatic Keyframe Onion Skin?

Is it possible to set the onion skin to automatically view the previous and next drawing/keyframe rather than just a specific numbered frame distance? If you have drawings that are spaced unevenly I'm having to manually set the onion skin on the correct frames each time which takes a lot of time for each drawing. Most other apps just automatically view the frame that was drawn on rather than a drawing that's a specific distance away?