Date/Event Based Unit Triggers?

[Red Harvest]

Does RTW allow Date/Event based triggers other than standard building or Marian_Reforms? What I'm wondering is if I can set new legion stats up for new units to be triggered at specific times as part of a mod:

Start mod at ~320 B.C.: Hoplite Roman armies (Servian styled armies), simple javelin, slingers, and cav

Capture of Samnium or ~300 B.C.: End of Roman Hoplite availibility, pre-Polybian legions (early 2 types Hastati w/spears oval shield w/wo pila, early Principes w/o pila, early triarii w/rorarii & ascencii that make the unit a bit weaker)

241 B.C. or Romans capture Sicily (End of 1st Punic War): End of pre-Polybian units, start of Polybian legions--but with slightly weaker attack stats for hastati principes because this preceeded adoption of the hispanic gladius by Roman legions--lower quality swords available.

210 B.C. or Romans control 3 Spanish territories: Hastati/Principes get improved gladius.

[NicSO]

But.....Its not OK I think because after the game starts u are making new history. It would be cool to put triggered event when romans conquer 2-3 Spanish provinces...etc.