Yes. But it's sort of a workaround. In Squeezecenter's settings, designate one drive/directory as the Music Folder. This is the directory Squeezecenter looks for your music. In order to access music on other drives (or in other directories on the same drive that are not a subdirectory of the main Music Folder dir), create shortcuts to those other drives in the Music Folder dir.
For example, I have music on two different drives. The drive/directory structure looks like this:
H:\AUDIO
\LIVE_A-Q
\STUDIO
J:\AUDIO
\LIVE_R-Z
I designate H:\AUDIO as my Music Folder. This gives Squeezecenter and my playback devices access to the AUDIO and LIVE_A-Q dirs. Then, within H:\AUDIO, I create a shortcut named "LIVE_R-Z" that points to J:\AUDIO\LIVE_R-Z. Now, when I navigate to my Music Folder, I see both the directories and the shortcut: LIVE_A-Q, LIVE_R-Z, STUDIO. Selecting LIVE_R-Z from my Squeezebox or Boom simply follows the shortcut and opens the directory J:\AUDIO\LIVE_R-Z