The body part (i.e., the hand) is already parented to the forearm and a child (the hand) can only have one parent.

A parent, however, may have many children, e.g., the hand (parent ) has 4 fingers (children) and a thumb (child).

cheers,
dr geep
;=]

Remember ... "With Poser, all things are possible, and poseable!"

cheers,

dr geep ... :o]

edited 10/5/2019