Strategic Event Scripting?

Is it possible to mod in strategic event scripting? This would be similar to the Marian reforms but might take the form of:

1. A region is conquered by a faction (or factions.)
2. A specific date is reached.
3. A faction is eliminated.
4. A territory is lost.

After some event, then various changes might apply...

An example would be Rome adopting the Spanish Gladius upon conquering Carthago Nova and thereby getting a weapons upgrade for Principes and Hastati (meaning I would need to reduce the initial melee stats by the same increment for the early game.) This could also be done by date. In MTW we had era's.

Another example might be limiting Roman archer auxilia to the conquest of some Eastern province.

Moving back in time to a modded map it would be interesting to have a Roman hoplite army (Servian) up to some date or conquest, followed by the pre-Polybian legion (name escapes me at the moment) up until the conquest of Samnium, then Polybian legion, then Imperial/Marian Reform) army.