Maybe an exemple will help.
In the FPW scenario, Carthage has the option to recruit Celtic Mercenaries, and this option can regenerate.
The relevant section of the script is this:
SelectFaction = $CAR
StartEvent = evt_nam_CAR_Hire_CelticMercenaries_Regen|5|0|NULL|NULL|NULL|NULL
MinDate = -264/01/01
TurnIndex = 1;3
Probability = 15
ActorDisabled = $gmaOptionMil;CAR_Hire_CelticMercenaries
EvalRgnOwned = $Gades
EvalEngagementPts = >=;5
EvalMoney = >=;100
EvalVP = >=;5
GenTextMsg = opt_notify_CAR_Hire_CelticMercenaries_Regen;1;NULL;NULL;NULL
ChangeActorPool = $gmaOptionMil;MaxUse;1;ImageID;Event-Img_Mercenary03.png;Money;100;EP;5;VP;5;Title;opt_title_CAR_Hire_CelticMercenaries;MsgString;opt_desc_CAR_Hire_CelticMercenaries;ToolString;opt_hint_CAR_Hire_CelticMercenaries;SubType;CAR_Hire_CelticMercenaries;
NULL = NULL
So, this regen event can happen 5 times, starting from -264/01/01, only on turns 1 or 3 (turn zero is January), with a very low probability of firing (15%), if the option is not active, and only if Gades is owned and resources are available.
The relevant string text in this case is:
The option will allow you to recruit Celtic mercenaries, at the cost of some money, EP and VP, and can be reissued up to 5 times in the game. Use them wisely…
Hope this helps
Regards. Looking forward to hear more about your scenario