If you only have 1, or have too few to stand up to what you figure he is sending over, you don't even have to send them somewhere else. Just watcht he incoming attack, and then when it gets to be about 10 seconds or less away, send them out on anything, raid, whatever...then when the attack hits, you can go to your rally point and cancel your attack and they come back.

Works if you rare online, if you are worried about when you are offline, send them off somewhere they should be safe, as reinforcment, or an attack that will take a long enoug time.