Trigger that activates only if other objectives are complete

[M1A1MG]

  Hello all;
Hoping to get some guidance here.  I have a mission where I must capture a town as my first objective and set hostages free as my second objective then occupy and hold a defensive perimeter(Obj_3). They must hold the perimeter for 15 minutes in order to accomplish the mission, But objectives 1 and 2 must still be complete. How do I get my objective 3 trigger to activate only if 1 and 2 are still complete?

[Seven]

I think this doesn't really belongs in advanced scripting, but to answer your question:

in the activation field of objective1 trigger add ob1 = true & same for 2nd objective ob2 = true
Set up your 3rd trigger and in the condition field put this && ob1 && ob2

Greetz