I'd like to know what txt files to edit to remove the walls from most Barbarian rebel towns.

I understand that this is a teensy bit historically inaccurate, being as even the most primitive of peoples would have understood the principle of building a wall around your settlement to protect it from raiders and so on, but for me, seeing as most battles between 'barbarian' tribes were skirmishes and not seiges, a greater historical inaccuracy is being commited, because most of my battles are seiges.

Ideally, what i'd like is for all barbarian buildings to be invisible, and for the unit placement layout thing to be altered so that when you assault a barbarian city and move to the battlemap it looks just like an ordinary field battle. I imagine that this, however, is beyond my skills, but hopefully I can manage the wall removal thing.