Photoshop :: Is There An Easy Way To Darken 200 Files Quick For Game Map

The pic on the right shows what I'd like to change. Problem is the borders can be tedious to do one line at a time. That is brush set at 1 pixel wide-dark gray. Then draw one map line. Then change to light gray to do center of line then draw right next to other line without messing alignment up. Then finally going back to dark gray to draw once again to other side of border line.

What would take a pro 5 minutes because he would know the shortcuts would take me hours to do these map changes. So could anyone tell me how to create a custom brush 3 pixels wide that would have the center pixel be lighter gray while the outer 2 pixels of line would be darker. I know how to use color picker to match with what's already in the game so you could skip that. I would just like to know how to create a custom brush that could do multiple colors in one stroke. I'm using XP and CS2 BTW. If anyone would like the targa files that make up these 3 regions in the game to mess around with I will send them.