How can I add Gesture - hand poses without erasing the animation on the hands

I only want to change the pose of the hands in some places but when I try doing so I lose the animation on the hands I want to keep in other areas on the Timeline.

I’m using the Edit Motion Layer Menu and setting the Gesture keys in Body Part Mode.

Here’s my progress so far:

You can do this by isolating “troubled” area of the clip and working out specific bones within the area. There are a couple of ways to isolate the area.

  1. Simply adding a key for whole body some time before and after troubled spot at the timeline and work in between for fixing intersection of the body parts for instance.
  2. Using Animation layers and controlling influence of the particular layer within area of trouble with weight keys.