Mirror and trees

Hi,

I'm a grasshopper user for a while now but it have always been a self learning process. and for some reason, I never get to fully understand how trees and their organization works.

So I have this problem...

I have a variable set of rectangles and planes based on their center.

Then I have points on one side of the rectangle.

I need to mirror the points based on the rectangle they came from

as I probably didn't explained myself properly I made a file where you can kinda see what I meant.

Any help are appreciated,

Thanks,

NC