Product variations as a single order on cart page?

Using this code I have out putted my product variations as a table

Does anyone know how I could have only one Add to Cart button, so that a customer could pick 3 of size 7, 12 of size 8 etc. and just click Add to Cart once… making this one single order?

Thanks for any help
Joe

http://wordpress.org/plugins/woocommerce/