Setting Up color Options

[Honeymay]

Need some Help! 

I currently have the Dawn theme set up for my  Website. I do Customs Tumblers. I have several different colored glass cups and several designs. I made a product listing for each design, but now I am trying to add the color options. I am trying to add the color selection for each design listing they can pick, without double placing the quantity of colored cups I have. Example, on design 1 I put I have 5 pink cups, 5Red cups , and 5 blue cups as the color options. And on Design 2 I put the exact same options . However, if someone goes to buy 1 blue cup from design 1 to request, it will not update the inventory showing I only have 4 blue cups left on all designs, and makes it hard for me to track and have to modify all the designs to show only 4 blue cups left . To sum up the question , I am trying to make an inventory list of color options that are set for ALL my designs to track on, not individually. Hope this makes sense lol Thanks in advance