Constraining Moviclips

Hi
Dose anyone know if it is possible to constrain on moviclip to another at run time, for example when you drag one moviclip it is constrained to another.
You could for example draw a cross shape - convert is to an mc and then constrain another mc to be dragged along the cross shape.

I have attached an example of what I mean

Cheers for any help with this one