Help connecting 2 buttons to 1 led

So, I am working on a fiber optic firework display for the museum where I work. There are 6 leds, each a different color with 1 button connected to each led, simple. Now, I need to program it so that you are able to "mix" a couple elements to create a color. So, essentially I need each button to connect to one led, then a couple of those same buttons also need to connect to a single led of a different color. Does anyone have any ideas? Here is a simple diagram of what I need.

Color: R Y G B W O
I I I I I I
I I I I I I
BUTTON: O O ------ O O-------- O O
I I
I I
Blue Orange

if button 1 then pinred =true
if button 2 and not button3 then pinyellow=true
if button3 and notbutton2 then pingreen=true
if button2 and button3 then pinblue=true
etc..

As you have six buttons a lookup table (64 elements). You then read the state of each button, put them together and lookup the output you want. Then write the output for each pin. IF you pick the pins for your LEDs correct so that they are all on the same port you can do the output with a single port write. You could do the same with the buttons.

Ensure that the lookup table ends up in progmem not ram.

Get the idea of buttons being connected to LEDS out of your head - You have inputs, outputs and something which transforms the inputs to outputs!

Mark

Thank you everyone! This helps immensely.