What joints and how to use them to produce the below desired effects?

Let's assume we have three Objects with rigidbodies attached to them and let us call them Obj1 Obj2 Obj3.

I want the following:
1) Obj2 to be fixed to a point relative to Obj1 unless a force greater than a specific amount causes their bond to break.
2) The distance between Obj2 and Obj3 to remain the same unless a force greater than a specific value is applied causing their bond to break.
3) Obj1's and Obj2's rotation will not depend from one another.
4) Obj3's rotation relative to the centre point of Obj2 will be equal to Obj2's rotation.
5) Obj2's rotation will not be affected by Obj3's rotation.

To clarify things: Obj1 is the Body of my character. Obj2 is the shoulder of my character. Obj3 is the elbow of my character. The above will produce a realistic result. Also Obj1,Obj2 and Obj3 are spheres.

Any help appreciated! Thank you in advance.