2 Rigs interaction, One rig griping second and throw, how to do it ?

[Anonymous]

Hello everybody, I am looking for an advice how to make a proper interaction between two rigs.
What I am trying to do is fighting scene, where one dead man is griping second dead man leg, making a twist and then throwing him away.
I was trying to it by locator - Putting whole rig under locator, then parent constrain to the hand control of second (throwing) rig. but after that rig stays under the locator, then everything snipping back and after turning key off, rig is getting to the rest position [when I am turning rest position off - then everything about considered rig is moved down ;-(, I think this method is bad, even if that had worked, leaving rig under the locator forever seem to be bad solution.

Thank you for any advice, I am really upset about my weakness.