Best way to color multiple groups in CS3

I provide resources for other designers to purchase to help them create certain old print style effects. The problem with this is that I need to make sure that it works in older versions of Photoshop. The problem I'm having with CS3 and CS4 is coloring groups without the ability of masking a group with a solid color. I've tried Gradient Map which works if placed inside a folder, but this doesn't work over 2 groups like in the image below. Is there a better way of easily changing the color of group(s) in older versions of PS?

Thanks Ian