To be honest, what you're describing doesn't sound too inituitive to me, so I question whether your report consumers would really understand what is happening and why.
Anyhow, off the top of my head, the workaround I can think of, is to use a parameter for your list of categories to select, rather than a quick filter. You'd then create a field called [Revised Sales] or similar which would be something like..
IF [Category Param] = 'All' OR ([Category] = [Category Param]) THEN [Sales] ELSE 0 END*
*note completely untested
You'd then plot this [Revised Sales] measure against [Category] rather than the [Sales] measure.
The drawbacks with this though is that
1) the list of categories in the parameter is static, so any new categories added into the data won't be available for selection.
2) you can't have a 'multi select' options in a parameter, so you canonly show 'All' categories with their values or just one at a time.
3) I don't whether you might be showing anything else on your dashboard that should be affected by this 'filter', so this concept might not scale.
Hope that helps.