I want to make a mission where if a ship of a certain government boards the player, then the player is forced to play a "slave" mission string. I originally thought I could have an always-running misison that fails when the player is disabled. That mission would OnFail Sxxx another mission which would cause an invisible 1-armor ship with a suicidal weapon (that ship is an enemy of the slave-driver government). The mission that caused that ship to jump in would require the player to protect it. When the ship died, the missions OnFail field would set some bits and start another mission and some other stuff triggering the storyline. There is one flaw with this plan: If the player is boarded by another government (non-slave-driving) and a slave-driver aligned ship is in the system, the mission will still trigger.

Any ideas?

I've thought of another way to do this: make it trigger a mission that randomly makes order fleets (sometimes, sometimes not) appear in-system and try to board the player. When the player is boarded s/he fails it.