Maybe it's not that clear.
More than an event, i will refer to it as a function, where every function is a global function. I mean, you create an NPC with some standard configuration. That NPC goes to a database, custom named (say, function NPC_hair(hair color,eyebrows color)). Now, when you create a second NPC, you have the option to call for the configuration of the first one, with some custom changes of course (call NPC_hair(red,blue)).
SO, if you need to change this function, there is no problem, you go to the database and change it, so each time it's called it refers to the main function instead of some independent copy wich had to be changed by hand.
So, using you terminology, "This Event" should call "Event A", because it's global, in the way of being accesible by any other event, not because it's variables were global. Not "instead" of a global event. So that way every event would be easily updatable and also readily accesible by any other event.
I must say i have no idea if its already implemented. I'm waiting in line for ther next version so i could finally complete a tutorial.