I have a hierarchy as follows ::
1. Region as top most level (eg. APAC, EMENA, US and CANADA etc.)
As of now, I was able to plot only cities and countries on the map as they are standard and easily identifiable by Tableau.
I want to show the regions also. I want to be able to define the regions as per my business rules and then show them on the map. If the user clicks on particular region, then the countries in that region should get highlighted and so on.
Please let me know if anybody has done this before and if yes then how.
I think you will have to wait for Tableau 10 currently in Beta
See the link above
Go to Section Answers through analytics - Custom Territories.
This is exactly what you need and so do a lot of others.