Separate Move and Music folder in Itunes?

I have a macbook air and I like using it to watch movies and listen to music on the go. Since I thought I would only use the air for document editing, I purchased the smallest hard drive available. While I don't have a lot of music, I do have a lot of movies that I have on my hard drive (Bought off Itunes) I noticed that itunes copies the music and stores them in a folder in the library. Also, the movies are stored in that folder. Does anybody know how I can change the preferences to where Itunes will get the music from the library folder, but look for the movies in another folder (external hard drive)?
Thanks

If you go into the iTunes preferences and uncheck the box for copying files to the library, you can simply add the files on the external drive to the library and they won't be copied to your hard drive.