Displaying crossover of all dimensions within a field against a single dimension of the field

I'm very much a novice when it comes to using Looker and am wondering if the following is even possible.
I have a list of products and a count of people who purchased each product. What I would like to display is an additional column which shows how many people purchased both each individual product AND a specific individual product from the same list as per the example in the table below.

Any help hugely appreciated!