I believe this should work..Just do the same for NE and Undead, and add more units than just their main starting building.
Code:
Untitled Trigger 001
Events
Map initialization
Conditions
Actions
Player Group - Pick every player in (All players) and do (Actions)
Loop - Actions
If (All Conditions are True) then do (Then Actions) else do (Else Actions)
If - Conditions
(Race of (Picked player)) Equal to Human
Then - Actions
Unit - Create 1 Town Hall for (Picked player) at ((Picked player) start location) facing Default building facing degrees
Else - Actions
If (All Conditions are True) then do (Then Actions) else do (Else Actions)
If - Conditions
(Race of (Picked player)) Equal to Orc
Then - Actions
Unit - Create 1 Great Hall for (Picked player) at ((Picked player) start location) facing Default building facing degrees
Else - Actions
...