Best way to implement real-time reflection?

Hi everyone, I’m trying to implement realtime reflection for a grid I use in my game. It doesn’t need any ripple or fancy water effect, as from my point of view is just a simple copy of the group I have, scaled in the opposite y direction, repositioned and faded with a mask.

Now if that would be static a simple display.capture() would do the trick, but since I’d like the reflection to respond to the element of the grid moving, it gets a little more complicated (display.capture hogs the resources). Any idea?

Thanks a lot.