Rotate bone around object's axis?

[JunkerKun]

What I mean to ask is:
Imagine we have a torso with a hand. It's a skinned mesh.
I rotate the hand on Y axis.
Then I rotate the torso on Y axis.
Now what I want is to rotate the hand on X axis but not the one relative to its parent (torso), the one that is local for the whole object instead.

Is it possible without adding more bones to the model?
If you need a picture I'll draw one.

[kornwaretm]

just don't parent the hand to torso?

[JunkerKun]

just don't parent the hand to torso?

And I can keep the bones ierarchy with that... how?
Also, I don't think 3d modeling software even allows that.