Ok, so you have dynamic bodies.
In this case you might have a look at these posts:
panda3d.org/forums/viewtopic … 9754#89754
We have added suppoprt for modifying contact data about 8 weeks ago. It is limited to the ‘contact added’ events, and the intention has been to modify friction.
I don’t see how this helps in your case, but tell me if you are successful or not.