You can automatically update exchange rates just for some currencies.
Choose File > Currencies.
Press the Update Rates button in the toolbar and choose an option from the pop-up menu.
All Currencies: Choose this option if you want to update all rates.
Found Currencies: Choose this option if you are searching currencies and want to update rates just for the found currencies.
Currencies in Menu: Choose this option if you want to update rates just for the currencies appearing in the Add Currency and Switch Currency menus.
Selected Currencies: Choose this option if you want to update rates just for the currencies you have selected in the Currencies window.