Change Key-Colors on pressing specific Key

Hey, Iam trying to design my Keyboard for the complex Sci-Fi MMO EVE online, there are a LOT of buttons to remember, with a lot of modifier keys, like pressing D is something completely different than pressing Alt+D. So I would like to really design a nice Color-Framework for the game. But Iam struggeling to find solution for lighting up keys in a diffrent color when you hit for example a in-Game modifier key. For example I want to have my Keyboard mostly Blue, but when I press (AND HOLD!) ALT, I would like to get most of the board dark and only light up like A, C and B. Or simply change colors of those Key. Unfortently I only found a solution to change the color of the exact key Iam pressing, not changeing colors of different keys... I assume there must be a way to achieve this, but I couldnt figure it out. Thanks in advance and best wishes! :)