Good question - I'd like the answer to this too.

When playing KH, I prefer not to recruit troops from small towns or large towns in Greece, only from cites with more than 6,000 people - apart from town garrisons or when under invasion. So Rhodes is the only supplier of native troops in my early KH campaign.

Otherwise, my KH armies are made up of family members (love those Spartan bodyguards!) and mercenaries. KH can earn lots of money, city populations are better used as money-making, tax-paying civilians than as troops. So I absolutely adore hiring armies of mercenaries when playing KH.