In edit mode, you will see the balls have a single root node. You can adjust and animate position, rotation and spring for this to control them both together or set it to off to let the physics take over. They do however both react to collisions independently.
If you want a more natural or defined shape you will need to adjust the morphs.
WeebUVR has some great gens morphs which are animated in their scenes.
You can also use collider editor once you have morphed to the shape you like to get better independent movement when they contact the legs, another surface or character.
https://hub.virtamate.com/resources/collider-editor.183/