Configurable Product should be able to do this example.
Price for a new teir is 12 pieces.
A person buy 6 red caps and 6 blue caps of same style.
Blue cap is sku 196-123_001
Red cap is sku 196-123_002
So when a person buys the 6 red and 6 blue it should be second tier of the total quantity.
It is however will still be first tier by the way the program is right now becuase it will seperate the color into its own items.
So a feature is being about to have configurable product where certain items change but it is still in same group.