I have a light emitter rotating around a vertical moving null (imagine a spiral). While the particles animate on I also have them Y rotating using world transform. Works great. However, when I duplicate the emitter light and change its position World Transform seemingly uses the anchor point of 0,0,0 of the first emitter and the second emitter rotates around the first. Make sense? My idea was to duplicate the light emitter many times instead of duplicating the instance of particular many times. Is there an expression that will force World Transform to view all emitters as 0,0,0 so it will rotate in absolute center of the emitter?
Why do you want so many emitter lights? Are they going to be moving in sync with each other. What is wrong with duplicating the particular layers? You are going to have to do this anyway if you are going to be changing the particles. Why not just apply more particular effects on the same layer and use a screen or add transfer mode? Not sure exactly your problem or what you want. Can you be more specific?