How to get two control rig physics solvers to interact with each other?

Does anyone know how to get two characters to respond to collisions between each other using control rig physics?

I have a control rig and have set physics on the neck and head bones as simulated physics components.

Then I have a kinematic physics collider on the hands. If I add two characters to the scene, each using the same control rig, they can punch themselves in the head and it work, but they can’t punch each other as the collisions between the two don’t seem to be simulating in the same space.

Both can collide with world objects but just not each other.

Any fix for this?

Thanks