How to implement global AI and Activities?

For a project I'm beginning work on, it is required that I keep track the activities of all the world's civilized NPCs and important notable "wild" NPCs. In terms of actual ramifications for CPU load, I'm concerned that keeping active tasks on hundreds of off-screen NPCs will be unhealthy for the game.

I was told that I might consider writing a separate logic server application in Stackless Python to do this with minimum CPU strain, but I'm wondering, if this is something I can integrate with Unity?