Grouping Country Name

Hi everyone,

I have few columns in my data set.

RegionName, CountryName, Variance.

I need a chart which looks like below

The bars indicate variance for each country. Few bars are grouped together which indicate that these countries are from a single region. Next group of bars indicate another region. 

I am able to create a chart this way. This shows variance for different regions and when I drill down a particular region I can look for countries. But I need my chart as mentioned in 1st image.

Any kind of help is appreciated.

Thank You.