Preloading

I understand the whole idea of a preload, and have made a number of preloaders, but they always just load the whole MC, and I’d like to set something up where I can preload different sections (levels) of my file (a game)…whether I do it by scenes or whatnot.

I know I could load and unload separate MC’s in and out, but they always seem to run slow when I do that.

Any ideas/source code somebody could offer?