When requesting help or assistance in the Community Forums please attach a packaged workbook or at least some sample data so that the Community users can better assist on the issue.
As for the desired result that you are looking to achieve, I would check out the following section of the product help: Use Parameters to Make Views More Interactive - Tableau
Hope this helps!
1 of 1 people found this helpful
As Patrick mentioned answering this definitely needs more information.
Without that only calc. I can think of this basic one which I am sure you must have already tried ...
if UPPER(Region) = 'SOUTH' or UPPER(Region)='WEST' Then
Depending on how/what you plan to visualize, the solution could vary.