Update simple cart Item that belongs to a grouped product

Hello,

Case:

I have a grouped product "G" that has 3 simple products tagged (say S1, S2, S3). G has attribute "view individually" set to true, while this property is set to false for S1, S2, and S3.

Now the flow:

1. User goes to website.com/G and adds S1 to cart.
2. User goes to website.com/cart, and would like to edit his selection (say wants to change the size attribute of S1 from small to medium). But since S1 cannot be viewed individually, "edit" link does not appear for this cart item.
3. So user tries to manually go to this page to see if he can still edit the cart item: website.com/G?updatecartitemid=S1_id. Unfortunately, it redirects to website.com/G.

So the question - is there a way to edit a simple cart item that belongs to a grouped product?

Please help. I believe this must be a common use case, but since am new to nopcommerce, this is eating up way too much brain power.