Custom options form for xcart

I need an xcart expert to set up the quantity for each set of contact lenses to be taken from product options. Something along the lines of: if product option title = 'Qty' than add the value of the select boxes up for both left and right eye and enter it into the cart session as the product quantity. You can see the options here: [login to view URL] Take a look at the first featured product to view the options. Than price will be Price x (Qty Right + Qty Left) Please only bid if you know the xcart system really well. I need this done ASAP. Thanks Troy