Not quite. If you create a documents folder on your second drive. Then move your documents into it. You can include the new folder in your documents library as in this tutorial. Library - Include a Folder
. This is the way I do it. My documents library has 5 folders included in it. Only one of these is on the Windows disk, the normal My Documents folder as some programs insist on using this.
I've never had the need to use either of those methods so I will leave it to others to comment.