Complicated Chart - top N + additional condition

Hi guys, I've been struggling with defining a calculated table for display in chart based on two separate criteria.

For example, I would wish to include top 5 countries + all countires in North America, based on their latest GDP.

Result would be sorted by GDP in latest year, compared to the same period previous year.

I have table with countries and gdp, year, and month.

And also table wich defines country and continent.

I tried to do it by making summary table, ranking the countries, etc, but have not reached the solution.

I would be obliged to get the way to do it 🙂

Thanks!