Hello, jmartyniak!
Have you tried to use Buy together add-on? Please read this article http://kb2.cs-cart.com/buytogether#3 to learn how to set it up and add "buy together" products.
Best regards, Alt-team
Thank you for your response, It looks like the Buy Together functionality changed in 2.2, because before I thought that it was it's own product.
I could make that work, but it isn't really the best use case. Because in this case you would have to create Buy Together combinations for each combination.
The perfect use case would be to put the item in the cart and then get up sold one or more of the other items when you are checking out.
-John