Nah mate there's a MUCH simpler answer
In your motion panel, in the list of controllers, click the very top controller (Transform: Position/Rotation/Scale), and then click the "assign controller" button....in the window that pops up, click "Link Constraint".
Now, in the motion panel, you'll have a set of new options that will allow you to animate links. Basically, just set the objects you want the pallet to be linked to, and at what frames. The link constaint controller will do the rest! (ie, "animate" the links--swap them--at whatever frames you choose)