startDrag(); along a custom path AS3?

Hi all

I was wondering if anyone can help me. I have recently made the shift from AS2 to AS3.

I am currently working on a job where the client would like a startDrag(); function on a movie clip. I got that already, it was easy enough to pull off.

The problem I am sitting with is I would like the startDrag to only work on a custom path I have specified.

For example it’s a car on a track. I only want the car to orient to the tracks path and nothing else, when dragging it with a mouse. Can anyone help me on this? I would really appreciate the help?