Conditional shipping option?

[split63]

You could try customizing the class:
/includes/classes/shipping.php

      for ($i=0; $i<$size; $i++) {
        if (is_array($cheapest)) {
          // never quote storepickup as lowest - needs to be configured in shipping module
          if ($rates[$i]['cost'] < $cheapest['cost'] and $rates[$i]['module'] != 'storepickup' and $rates[$i]['module'] != 'usps') {
            $cheapest = $rates[$i];
          }
        } else {
          if ($rates[$i]['module'] != 'storepickup' and $rates[$i]['module'] != 'usps') {
            $cheapest = $rates[$i];
          }
        }
      }

I made that change, but nothing happened.
Just to be clear. There are two cases:
1. Domestic shipping - Always and only USPS priority
2. International shipping, Always Fedex, and sometimes also USPS FC if FedEx>$40

It is case #2 that we are discussing. When the FedEx is >$40, USPS FC appears, but USPS FC is always by default selected. I want FedEx to always be default selected.