Some of one size and some of another, but of one item

[jfelds]

Is there a plugin, or combination of plugins that will let my customers pick one item style, let's say it's a shirt, and then order 5 mediums and 10 larges, and still get the quantity discount that would be applied to an order of 15 shirts? If it's not clear what I mean, let me know so I can clarify.

 

Thanks,

~Jordan