Constrain a hand to hold onto a rail while the rest of the body moves

Hello,

I have been trying to figure out if there is a way to constrain a hand or foot to one point in 3D space e.g. a null, while the rest of the body moves. I have played with Animate2's constraints and while they work on standard objects, they don't seem to work on hands.

What I want is the figure's IK to adjust the attached part of the arm IK chain to where the hand is positioned. Imagine getting out of a chair with an arm rest. The hand should stay on the arm rest while the rest of the body lifts and the arm moves too.

Are there any DAZ standard constraints? Can this be done some other way?

Thank you.