Hi, I'm trying to list a unique item (necklace pendant) but have an option to choose the chain length between 3 variables. When I add the lengths as Attributes, it then has a quantity of 1 for each attribute, which I don't have. 

Is there a better way to do this? It would be nice to have a selection, and once one selection is made and the product purchased, all the other attributes are changed to 0 so the item can't be ordered again. 

Thanks