Foreign ventures/military settlers
Most (all?)civilized factions have acces to "buildings" that give malus to pop growth and bonus to law. From the description it looks as if they simulate colonization of foreign territory by citizens of city in question. Do they indeed trigger some events that increase pop/decrease unrest in newly conquered cities?
Re: Foreign ventures/military settlers
No, it isn't possible to effect foreign territories with the building. It only effects the town that it is built in.