Only the shoulder.
Perhaps the blending zone has to be changed a bit. Depends on the pose. If there is a break between shoulder and collar, carefully change the joint angles. If you did it a few times, this is done in a few seconds. Better and easier than dealing with 1000 morphs and magnets. I'm really a morph-freak - but bending is nothing morphs are good for because there are so many side effects.

By the way: While working on joints P7 is very helpfull because of the new Undo feature.

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