How to sort cart products using new variable?

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I have a module that is creating a new column (id_hash) in the cart_product table. By default prestashop groups products based off of the values in the cart_product table. I have figured out how to include my value in the new column, but I can't figure out where I need to override/add code in order for my new value to be taken into consideration. 

 

My current understanding is that somewhere the code looks at cart_product and compares id_cart to look for products for this specific cart.. it then looks to id_product, id_product_attribute, and id_customization to see if it is the same product and if it should simply be incremented or if there's a difference and it should be a new row in the cart. My goal is to add id_hash as one of the things it looks at to see if they should be grouped together.

I have tried editing Cart.php, CartPresenter.php, CartController.php as test to accomplish this but have been unsuccessful thus far.