CMYK movie clip effect

I was thinking it would be simple to make a movie with 4 circles representing cyan, magenta, yellow and black with each being able to overlap to make a colour spectum by the user dragging the circles over each other. All good with the drag dropping movie clips but I have no idea how to get the transparency correct to represent CMYK with Flashes RGB colour pallet. Does anyone know whether this is possible to do? It doesn’t have to be 100% accurate but does need to provide visitors an idea of CMYK colour blending. Any help much appreciated.