Unit Spawn Triggers

Unit Spawn Triggers

Ok, I want to know how to make it so that when you have three of a specific unit, then the trigger stops until at least one of the units dies.

Spawn foories
    Events
        Unit - A unit Begins training a unit
    Conditions
        Or - Any (Conditions) are true
            Conditions
                (Unit-type of (Trained unit)) Equal to Footman
                (Unit-type of (Trained unit)) Equal to Knight
                (Unit-type of (Trained unit)) Equal to Rifleman
    Actions
        If (All Conditions are True) then do (Then Actions) else do (Else Actions)
            If - Conditions
                (Number of units in (Units owned by (Owner of (Trained unit)))) Not equal to 3
            Then - Actions
                Do nothing
            Else - Actions

after the "Else - Actions" is hwre the training will be canceled!
It's been..6months since i looked at WE!