airport ground vehicles

I can call jetways and fuel trucks and pushbacks, and I can open the exit, but I've seen some screenshots, like one of a 747 with all the doors open and a bunch of little cars scooting around, unloading cargo and stuff. how do you open those doors and call the vehicles that unload cargo?

The only way I know how to unload cargo is with an add-on.

I think I know what your saying. Press Shift + E 1, 2 , 3 , 4 which should open all the exits. Call for droppable objects by pressing Shift + D.