Tomas Skrivan shares a Python script he created for making the task of setting up multi-parent constraints in Autodesk Maya super easy.

This is python script for Autodesk Maya which makes animation with multiple parents dead easy

With the Multi-Parent Constraint script simply select the object that you want to animate, then select two or more objects that you want to be the new parents or pivots, and get animating. Currently the script doesn’t update the viewport in real time, but it surely will do in a pinch, making the parent constraint set up mostly automatic.

Check out the Multi-Parent Constraint Script for Maya here.