How Do I Combine Attributes And Quantity Packages On The Product Site?

[Wster]

Lets say that I have product with an color attributes with the values blue, red and yellow. I have 1000 pcs of each color. I want to sell in packages of 10, 50 and 100. I want to make it possible to choose color and type of package on the product page. If i choose a pack 10 yellow, I want the stock to decrease with 10, and the samewith 50 and 100.  

 

I can't figure out how to do it.

 

Any ideas how to solve the problem?