[Sombre]

Or you could just call the game when someone proved they killed that unit.

If you run a mod with the scenario game (in MP) you can effectively add messages and more gamesmastery type effects by modding units, spells etc. For example you could say the first person to conquer a certain province gets +1 fire magic on all their commanders, or you could have a monolith style unit in each person's starting province with a desription that changed to give messages from the Pantokrator. Stuff like that is technically easy, but would be a bit fiddly for the DM/GM/Admin/Host.