A few ideas:
Only way I can think of is an attach mover set to trigger control, with blockall actors attached to it to block the path.
Then have it open and move the blockalls out the way when someone aproaches them from the spawning side.
This would not stop someone from camping the trigger and allowing people to go back though the wrong way though
You could try zoning the corridor off and adding a zoneinfo, then setting a Zone Velocity so that it pushes them through the corridor in the right direction and stops them from going back the wrong way. (same techinque as the conveyors in DM-Conveyor, only more powerfull so you can walk the wrong way at all)
OR you could try warp zones, I've never tried them myself, but I guess you can make them so you can pass through one way but not the other...