Idea - "Hero Militia"

[Gnuoy]

I want to make a Metamorphosis type hero spell but you need to run to a Town Hall to cast it, or at least be in range of one, similar to the Peasant ability Militia. Anyone have any ideas how to implement this as basically and simply as possible?

 

[Chaosium]

I'd give some sort of aura to the town hall that affects heroes only but does nothing on its own, then via trigger detect whether the hero casting the metamorphosis has the aura buff, if not, cancel the cast

 

[Gnuoy]

Care to share any thoughts on this trigger?

Spoiler: trigger

• Militia start
  • Events
    • Unit - A unit owned by Player 5 (Yellow) Starts the effect of an ability
    • Unit - A unit owned by Player 6 (Orange) Starts the effect of an ability
    • Unit - A unit owned by Player 7 (Green) Starts the effect of an ability
    • Unit - A unit owned by Player 8 (Pink) Starts the effect of an ability
    • Unit - A unit owned by Player 9 (Gray) Starts the effect of an ability
    • Unit - A unit owned by Player 10 (Light Blue) Starts the effect of an ability
    • Unit - A unit owned by Player 11 (Dark Green) Starts the effect of an ability
    • Unit - A unit owned by Player 12 (Brown) Starts the effect of an ability
    • Unit - A unit owned by Player 17 (Wheat) Starts the effect of an ability
    • Unit - A unit owned by Player 18 (Peach) Starts the effect of an ability
    • Unit - A unit owned by Player 19 (Mint) Starts the effect of an ability
    • Unit - A unit owned by Player 20 (Lavender) Starts the effect of an ability
  • Conditions
    • (Ability being cast) Equal to Militia (Peasant Knight)
  • Actions
    • If (All Conditions are True) then do (Then Actions) else do (Else Actions)
      • If - Conditions
        • ((Casting unit) has buff Village Hall Aura (effect) ) Equal to True
      • Then - Actions
        • Unit - For Unit (Casting unit), start cooldown of ability Summon Tower (Peasant Knight) (Q) " over "60.00 seconds.
        • Unit - For Unit (Casting unit), start cooldown of ability Pocket Factory " over "60.00 seconds.
      • Else - Actions
        • Unit - Order (Casting unit) to Stop.

 

[Chaosium]

That's pretty much what I would do, the only thing I'm not sure of is whether ordering the unit to stop happens before the unit actually casts the spell