Quote Originally Posted by pezhetairoi
Just a quick slightly related question, then: The Gaesatae were mercenaries too, so why is it they are not available in the Gallic mercenary pools? o.O

Because the RTW definition of mercenaries and the one being used when the Gaesatae are mentioned are pretty different. In RTW a merc can be hired by absolutely anyone, in the ancient world there were plenty of mercs who were a bit more picky about their employers, the Gaesatae were one of these.