(GTA is an 18 rated game, and if people are offended by the word "sex" they should really get off the internet)
But what i'm saying is make a small application that has multiple choices and options to make your own callout, and when created, will create the corresponding file that will go into your game. You could even delete/edit already existing ones. Simples.
That sounds like sex. But I can imagine it being a little limited.
Unless you make an app that does it for you, with several variables added. Like;
Police units already on scene? [Yes/No]
Type of callout? [suicide/Robbery etc. etc.]
etc.
You can either create a new one or edit an existing one. Perhaps more user friendly than actually coding the INI files themselves.