Well there is a better suggestion - to limit the attacks against player or to implement some kind of maintenance for the units outside- it's kinda freaky and boring to wait 300 attacks against you to split count waves, to reconquer, and summon alliance units for such a large number of attacks. If the attacks want to spent so much time in front of the PC it is up to you, why the defender should pay for his inferiority complex and small ... well you got it.
Cheers, House