Thanks for the explanation Jean, I think my wording and certainly the image have been a bit confusing though. The situation is not quite like a planetary body orbiting a central mass.
I'm revisiting an old setup I had for a conveyor system, due to odd behavior as the rigidbody objects transition from one piece of conveyor to the next, specifically straight pieces to corner pieces and visa-versa. The straight sections use a set velocity to move all of the rigidbodies along the surface of the belt, then corners are very hacky, they parent each rigidbody to a rotating empty game object. The main issue is the velocity applied on the straight sections is not taken into consideration as they are transitioning to the corner section, there is a momentary unwanted acceleration as the force stacks on top of the rotating empty.
So it's a situation where the orbit is only ever around the Y axis. The rigidbodies must be fully active to be able to be knocked around by other forces, colliders and each other.
I'll see what I can do with joints, but I have a feeling that may get a bit messy in some situations.