Assuming this is an add-in to the single player campaign (or Awakening), I think triggered conversations are very difficult/risky to implement.
Triggered conversations are usually initiated using talk triggers, which are like regular triggers except that they can reference plots to start/not start conversations. Since triggers can't be created at run-time (using CreateObject), there is no way to introduce additional triggers into existing areas (a workaround to this is
here )
If you want this to happen in camp, it is a little more difficult since followers don't move around in camps in which case the simpler solution is to trap the area_postload_exit event and play your cutscene there. Have a script that will fire the conversation for the follower at the end of the cutscene. This would mean you would have to override the area script.
It's late here so there might be a better way to do what I've outlined in the above paragraph. I'd suggest checking with the other follower-builders (ladydesire, DLAN_Immortality) to see how they've done such things.