What is the best way to merge two iTunes libraries?

Hi all:

I wonder if anyone has a suggestion on the following situation. I have several Mac’s and AppleTV. I used an iMac for the sole purpose of making the library available to the network, and the library is located on an external drive since it is about 300GB.

Now, I have replaced a standard MacBook, and would like to use the old one instead as the “media server”, however, it has it’s own iTunes library on it’s HD since my girlfriend used it.

Now, the question is, how do I plug that drive into the MacBook, get iTunes to import that other library without actually moving the files (size!), and without creating a duplicate of every file (which is what happened the last time I used import -> consolidate).

Thx in advance

And PS
There are about 20 movies residing on the AppleTV now that haven’t been synced to the old library, obviously I don’t want to lose those either.