Let's say you have named the chopper as bh and your men are i1 to i6.
unassignvehicle i1
i1 action ["eject",bh]
unassignvehicle i2
i2 action ["eject",bh]
unassignvehicle i3
i3 action ["eject",bh]
unassignvehicle i4
i4 action ["eject",bh]
unassignvehicle i5
i5 action ["eject",bh]
unassignvehicle i6
i6 action ["eject",bh]
exit
Do that as if you werre doing a normal mission but in the "Unload transport" waypoint put [] exec "script.sqs". I hope that will work. That code is from my campaign, but I did it a little different, but I think that that ought to work.