troll nation

[Swan]

i want to make a ntion inspired on warcraft's troll.
darkspear,ice,forest and sand at least are the tribes i'll be using.
But i want to do something special:you will be able to recruit ice troll ony in mountain,sand trolls in waste,forest troll in forest and darkspear in coastal and swamp.
if a province is without one of this you will be able to recruit one random tribe.how can i do this?
for everyone terested here is a background of the tribes and the nation:
a) ice troll : few units,manly chaff(axe trowher and a meele axe wielder) and one elite that shoot cold like the goblins in ma jomon. they have commander: 1 lowly age(1w 1f/w/s), 1 big mage( 3 ran w/f/s),a priest with 40-50 heal.
b) sand troll: heavy armored,some with two hand sword other with bow and sword or spear. 1 low blood/death mage and a very good commander.
c) forest troll: light armored, full of range weapon and nets. some nature mage and a chief with super-precision.
d) darkspear: some meele chaffs, one sacred berserk with two huntin javelin( range str*2,dmg 5+str,magical,100 ammo)
and hunting spear( o dmg,2 atk,2 def,4 lenght,arm neg)
a vodoo priest(d/s/n) and a shaman(good dw, high def,low life 1 in all elemntals path, 2 100% f/w/a/e and 1 10% f/w/a/e

all the trolls will have high def, low hp,reg and recuperation, high precision and survival in their terrain.
in the capitol you can recruit all the units.
what do you thinnk of this nation(ma)?