I have a 2 different libraries in two laptops, my wife's and mine. Both are clogged with music we do not hear everyday. If I merge both libraries, it will amount to abut 20 GB or more. So, I would like to centralize the libraries on only one iTunes library located in an external HD and have the laptops keep only the music we hear often in their local libraries, and still have the external library to extract or dump songs. Is that doable or am I getting into a mess? What would be your perfect setup? Thanks.