Tried half and half a few times, different strategies/routes on the map. Always seem to get to a certain point and get obliterated by AI that starts furthest West.

Tried to put a pack together and chase AI commanders down, no success.
Tried to spread in all directions right upto mountain crossroad, north east corner and again get obliterated by most western AI.

Tried the emergency blockades to try concentrate on 1 AI at a time but again no success.

Maybe just missing a trick and its probably most likely basic. Any help would be appreciated.