Creating Google geochart with custom defined countries

[Paul Maural]

HI,

I am wondering if geochart allows to draw map based on custom defined
countries, which are basically combination of different countries.

Example :

To illustrate, take example of the 1st chart in
https://developers.google.com/chart/interactive/docs/gallery/geochart

Under 'Region GeoCharts' , country data is defined as :

var data = google.visualization.arrayToDataTable([
['Country', 'Popularity'],
['Germany', 200],
['United States', 300],
['Brazil', 400],
['Canada', 500],
['France', 600],
['RU', 700]
])

I would like to create a plot for (Germany + France) with value
(200+600), (United States + Canada) with value (300+500), and rest of
countries. I also like to have boundaries to be omitted between
combined countries so that my combination of countries appears as a
single country

How can I define such data?

Any pointer will be appreciated.