Breaking up G-code

I wanted to take a long G-code project and break it up into several jobs. I know I have to cut and copy the different parts into new files but I am not sure what codes I need to start and stop each part.

EDIT: I found this other way of doing this on another website but not really the answer I was looking for but I will pass this along.
“You break the machining up in rectangular tiles, with an overlap at least as large as your largest bit. For instance, if the model is 48x96 and you wanted 24x24” tiles, and you used a 1/8" ball, I’d make the machining boundary vector 24.125" and the adjacent tile the same so you get a little overlap on both to feather in the transitions. Just make rectangles that overlap and select the vector you want to machine and cycle through the set. Then save out each tile with a name and number you understand."

Depends on the software your designing your tool paths in - You can define areas of machining and create gcode files that do just that.