Can I cancel a unit's training through triggers?

[Evoroth]

I just realized that cancelling a training doesn't give an order. So, is there any way to do this through triggers? I can remove it when it has trained, and I can remove and recreate the building, but can I cancel a single unit?

 

[AceHart]

Cancel Training
    Events
        Unit - A unit Begins training a unit
    Conditions
        (Trained unit-type) Equal to Footman
    Actions
        Custom script:   call IssueImmediateOrderById(GetTriggerUnit(), 851976)

This would order the "Triggering unit" to cancel the training of a Footman as soon as it starts.