trigger covering base, player's group (west/east/etc) present, and in the conditional field check your objective ending variables.
always handy, especially in situations like this, to have variables to represent objectives done or failed. so for example, obj1 = false, obj2 = false, etc in the init file at the start of the mission, then as the mission progresses, obj1 = true when the first objective is completed (as well as your
"1" objstatus "done" ).
that way, when it comes to the base trigger, if you put in the conditional field not (obj1) and not (obj2) then the trigger will only fire if objectives 1 and 2 are incomplete.
reading back, that's not the clearest explanation in the world, but i hope you get the idea