Custom LED tail lights ?

[MZ 500]

I'm sure there is nothing out there for my car so I would like to make a custom assembly for it. I attached some pic's of my assembly the center section is a reflector as stock but I would like to have sequential LED's working from the center out on this pannel when the brakes are applied. The outer brake lights can come on right away. I just want the sequential part to work when I first apply the brakes and not repeat when the brakes are held. Clear as mud. Any ideas on how this could be done would be grate.

This is a GT light assembly for a 70 71 Torino.