Circuits newb, help with confusing power switch design problem

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So I am building a lighting control box, with a kit-built 4-channel color organ as the heart. There is a mains input and four outlets switched with SCRs that are triggered through audio circuitry that's all working just fine. What I'd like to do is add an A/B switch and a dimmer so that I can switch between the color organ circuit (4 separate outlets) and a parallel connection to the mains for all four outlets at once that's controlled by the dimmer. Can anyone explain how to wire this up? It's hurting my beginner's brain! The circuit diagram for the color organ is here: http://media.gibsontron.com/9935.pdf