Using a list box you can make an association in the datamodel, such as when you select Country then only ports for that country are filtered. This seems like the obvious way to proceed. If you are concerned that the list box does not seem enough like a button, then you can create 26 list boxes, each with an expression that says something like:
=if([Country]='China',Country)
This will allow you to output the countries one at a time and you can then add rounding on the Layout properties and remove the Caption on the Caption properties etc.
If you do not want to filter the data for each country, you can set up a variable that says which country you want to look at and then change all your expressions to include this variable, in the format $(vSelectedCounty).
A third option is to use Alternate States which allow you to make preselections of State Identifier that your charts then display. See section 14.4 in the QV v11 manual.
