Austria's finance minister said a Greek exit from the euro - or Grexit - would only be possible if Athens first asked to leave the European Union and other countries agreed to its request.Athens has called a July 5 referendum so that Greek voters can decide on whether to accept new, tougher bailout terms that the government itself opposes."The consequences for the euro countries are not nearly as bad as for Greece. It's clear that one country can under no circumstances blackmail the European Commission and the euro countries," Hans Joerg Schelling was quoted as saying in Sunday's print edition of Austrian newspaper Die Presse.