The trouble is you'd need a new action any time you make a new size of tile, and it won't work for irregular shapes. An AHK script would work on any size tiles, regular or irregular.
I haven't tried this, but the first solution that comes to my mind is to render out a color mask with the tiles all one color, then use an AutoHotkey script with the PixelSearch function to search for that color and Click with the magic wand tool to select it, then run a photoshop Action to switch to the normal map and…
Did something identical about a year ago for a pattern of shattered glass. Selected every shard individually by hand and ran an action to make randomly perturbed normals using average blur. I think automating that kind of process would require a script. Cant' see how to get around not needing some sort of conditional…