Hi Nadine,
OK, so now you have currencies ARS and USD, and you only want to see USD? You have 3 Destination properties that decide the currencies. I assume that among these 3, at least one is ARS and at least one is USD, and that's why you see both currencies rather than just USD a sin your latest example.
The other thing is that in your latest example, you want to have a non-symmetrical selection of Destination and Account. I assume you are in Italy, therefore BRJ would always be international but FCO could be both international and domestic To achieve this, you could have 3 more properties in Destination, holding tax accounts instead of currency, and then let the Account too be decided by the properties in Destination.
Hope this helps, not sure I understand your issue fully!
/Cecilia