Sorry if I wasn't clear. My setup will have probably 24 RGB LEDs. They will be in sets of 3 because of the 12v power supply. My issue is attaching multiple colors to the power but giving them different current limiting resistors. So, originally I had thought I would use the setup (I copied it into my last post) where two of the circuits are basically in parallel, to use the same power and music source (so on that diagram, the two parallel circuits would be, say, red and blue on the same LED). I hadn't noticed at the time that I wouldn't be able to use a common ground for them.
AG, I understand that I hadn't adequately prepared for this project, however is there any way to modify the current setup without having to get PNP transistors?