[General] Race/Faction Idea and help on something

[BlackRangerXIII]

I'm here to tell of an Idea that i'm toying in the back of my head
It's a Race/Faction: a Mercenary-type faction
where you can hire units and heroes and wood is only used for buildings
however advanced units can only be hired by the player when the Mercenary Contractor (a hero that is available from the start and has it's own limit, abilities and an ability known as contract hold which allows players to hire more advanced units and can be recruited with three other heroes) is in the field.
The problem is:
How can I make the Contractor System work without bugs or leaks and any suggestion on how to improve the system?

 

[Chaosy]

So basically units can only be trained when the hero is alive? Is that it?

 

[BlackRangerXIII]

So basically units can only be trained when the hero is alive? Is that it?

Only advanced ones can be trained while the contractor is alive
Civilian Contractors, Basic Infantry (footman-like unit) and heroes are trainable without the contractor

 

[Chaosy]

Well then you'd basically:

Event - unit is being trained
Condition - if unit type is equal to X and if hero is dead
Action - order training unit to cancel (google how to do this, you need custom script I think)