Roofmonkey, that helps me with my next issue. My kids started back to school today so I can now push them into their rooms to do homework. Your method allows me to share the music with all three computers.
My question was answered in this part of a Macworld.com article. Hope it helps someone else.
"Another option is to change iTunes’ settings so it doesn’t copy files when you add them to your iTunes library (the program’s default), but rather leaves them where they are. Doing so lets you keep some files in your local iTunes Music folder, and others on an external drive, or in another location on your startup volume. To make the change, look just below the iTunes Music Folder Location section in iTunes’ Advanced preferences and deselect Copy Files To iTunes Music Folder When Adding To Library (see “iTunes Preferences”). Now when you drag files into iTunes, the software will simply add pointers to those files instead of copying them. However, music you rip via iTunes or media you purchase from the iTunes Store will still end up in the standard location (the iTunes Music folder on your Mac)."