Permanently show a set of data in a bar chart

I've received a request that seemingly goes against how Spotfire is designed to work... but need to come up with a cunning plan of how to overcome!!!

Imagine you have a data table that looks like the following: 

Category Region Sales Value
Football North 35
Football South 45
Basketball North 25
Athletics  North 15

... and you want a bar chart showing sales value by the different categories, allowing a user to add in different categories and drill into differnet regional splits, but "Football" must always be shown on the chart. 

Backdrop: The context around the request I've received is that users want to always see the "sure thing" sales, but want to dig into the incremental opportunities. 

Any thoughts? My intial thinking was a R script that generates a new data table depending on what's selected but always including "Football", which is then used to plot the chart. 

(2) Answers