I don't think there exists a general method that applies to every multiple-floppy Macintosh game that has ever been made, unfortunately. I'm not aware of a general rule that defines where to put each game's files, because I guess that every developer chose how to name them and where to put them on his own. 
For some specific cases, you could probably find the original file arrangement of each floppy documented somewhere on the web, but you'll have to be lucky.