Multiple quantity fields on one product display page
I'm looking for what I guess must be a pretty rare use case for a product display page. The client we're developing this for sells books largely business to business and come in multiple languages.
I have set up three product entities each with a different language selection under a language taxonomy. They've been attached to a product display node and are displaying as expected there, allowing the user to choose what language they want the book to come in and then add to cart with a quantity field.
What I need though is to have a quantity box for each language and then one add to cart button to be able to add multiple languages at one time. It would display something like:
English: [ ]
Spanish: [ ]
French: [ ]
[Add to Cart]
If there is a way built into the core modules I haven't found a way. I have found the contributed module 'Commerce add to cart extras' (http://drupal.org/project/commerce_add_to_cart_extras) which actually does provide that exact form. The problem is I can't seem to configure a contextual filter in the view that would limit the product fields listed to just those attached to the node.
I'm both against a deadline and also really struggling to get this to work.
Does anyone have an idea of how to configure the view to see the referenced products OR a different way to solve this problem?
Thanks so much in advance!