Selection variable : Formulae to be put

Hello all ,

I have a characteristic called Country.

Now so many countries are coming through transaction like GERMANY., ITALY etc.

User is currently getting options to select country , they can select country as Germany and the whole report will be filtered based on germany.

Now they want another value in the same filetr which will be the ratio of Germany/Italy.

It means in the filte they should get option to filter Germany or Italy or Germany/Italy.

Please provide some information how to go ahead.

Thanks and Regards

Rupak nandi