Implementing custom joints/constraints?

I need a sort of constraints in Isaac Sim that none of the Physics joints provide. Is it possible to implement something like a custom joint? If so, it would be nice to get some directions on how to proceed here. What I need is something similar to a prismatic joint, that lets an object follow a curve defined by a set of points. Something similar to the movement of the spheres in this toy.

Kind regards

I actually do not want to model the precise physics here, just need an object that follows a curve.

If you needed collisions, one option would be to use a kinematic rigid body
and move it each frame based on the spline points manually.

You can also animate the object using keyframes:

or animate it in a third party tool and import that via USD.

Thank you. My understanding is that when I use a keyframe animation, the object is not controlled by physics anymore, besides collisions. What if I need the physics features like gravity or acceleration?

Is it possible to implement custom joints in Omniverse? My understanding is that Nvidia PhysX supports this.