Hmm. I would suggest looking into internal graphics work. Canvas plugin obviously also a way to copy and inject/paste the graphics. Also have a empty sprite with physics.
What you would need to do.
1. Create Physics Sprite
2. Paint physics sprite with image
3. On Cut Condition
- determine angle of cut and point of cut
- create two physics sprites based on the larger size.
- paint two new sprites with by copying the 2 sections(includes the overlap angel.
- use some trig to determine which part of the 2 new sprites need to be set to transparent. Looking up some canvas features. something like fillpath might work.
4. show 2 new sprites and remove old sprite
Now here is the thing. I haven't done anything like this, but I know plugins like canvas give you the ability to alter the image base. This is a requirement and only way to do it. good luck.
Here is a sample image of what I think you want to do.
This way you can make the graphics changes nessisary and then cut them into to new sprites. Good luck :)