How to get submesh controlled by collision shape?

Hello :smile:

first at all please have a look at this image:

What I am trying to do is to kink the end of the tube. All parts should get a collision shape except the ring at the end.

First i tried it with the KinematicRagdoll what results as expected - the rings at both ends are part of the collision shape. So now Iā€™m trying to do it by hand as you can see in the screenshot. So now the question: How can I get it worked that the ends of the tube are controlled by the physics and kink in the limits of the joint?
For your information: the ends of tube, including the ring, are submeshes for now.