Let others edit options in my shopping list

Hello,

I’m creating an e-commerce site that will allow a groom to select his suit and the suits for his groomsmen. What the client wants is for the groom to create a shopping list, then create a group that consists of his party where he will share the shopping list. Each of them would log in/create an account and already have access to the chosen suits, all they would have to do is select their sizes and add to cart. The problem is that I can’t find a solution for the last bit. Everything I’ve tried does not allow the group member to choose their size, they can only accept the list as is and add to cart. Is there a plugin out there that can do this?