Itunes to Mac and Laptop

OK - I’ve figured out how to move files from both Windows XP and Apple to the WD MyBook World.  It is now accessed by my Sonos System.  Here’s the question.

My daughter bought a new macbook and would like to copy some songs to her macbook as well as upload some songs.  Is there a way to keep the new macbook in sync automatically with the WD Itunes?  If so, how do I set it up.  ie can I use the WD Itunes as the primary server and treat her Mac as a device (like an Ipod) and still let her use her Mac as a server to her ipods/cell phones/etc.

Thanks for any help.