AS2 - throw / friction / snap

I’m stuck trying to achieve something in AS2. The principle is easy: the user can drag/throw a timeline (with thumbnails) around, but I want it to snap to certain positions. I’ve created an example to show what I need

You can already drag/throw the timeline around, but, as it slows down, I want it to always snap into a position where one of the purple rectangles snaps to the grey area so a thumbnail is always covering the grey area.

So when you throw the timeline hard enough, it would fly quite far (speed of timeline > attraction force of the snapping points), but as it slows down, the snapping force takes over and the timeline snaps in place.

I’m pretty clueless here so any help or direction would be greatly appreciated!