Calculate data inputs for Venn diagram

Tableau version: 2019.1.5

Hi,

I am hoping for some help with calculating the intersection (or not) of some data.  I've searched for an answer on the forum, but haven't found an equivalent scenario.

On sheet 1 of the attached Sample - Superstore workbook, you'll see Sales data by Region and by Customer Name (my data only has 3 regions so I've filtered out the West here).  I am trying to show 7 values:

Count of Customer Names with Sales in Central only

Count of Customer Names with Sales in East only

Count of Customer Names with Sales in South only

Count of Customer Names with Sales in Central and East only

Count of Customer Names with Sales in Central and South only

Count of Customer Names with Sales in East and South only

Count of Customer Names with Sales in all 3 regions.

There seem to be ways of creating the viz of a Venn diagram in Tableau, but I'm just struggling with the initial step of getting the data together.

Thanks!