not sure what you want to do. if you want to  have a characters arm move around and follow a characters leg while holding  the characters ankle   say their right hand, just go to figures and then IK and turn on the right hand IK. After that when you move the other character's leg the  hand will stay  on the ankle but may require tweaking if you move it too much.

now if you just want to be able to move 2 characters by moveing one   parent the characters hand to the other characters shin and you can mobe the  grabed character and the grabber can go along for the ride.