Thanks for the ideas Chirone...
If I understand you correctly, one problem is that you can't parent constrain something to two different curves (curves being the 'parent' or master).

I looked for attributes that change the pivot point, but in the list of keyable attributes, all I could find were things like 'rotate pivot translate x' or 'scale pivot y' which I have no idea what they do. I tested them and got very odd behaviour. As usual, my search in the maya help turned up no help. I'll keep playing around with different things, and maybe do some more rigging tutorials after the challenge is done.