I'm fully expecting the answer to this will be "that's not possible". I've got an effect I'm working on at the moment, building off a tutorial for creating a money style effect using multiple layers. The guilloche patterns are used as mask selection image that's been copied once for each time the patterns will be applied.…
I was expecting an answer like that. Group masks are out because the light has to effect a deep shadow layer more than the faint shadow layer ironically. Here's an example from the tutorial site. Imagine the light pulsing and pushing the linework around like shadows. That's the effect I'm after.