[Samba] how to view disk labels used by a user for his/her disk shares?

[Gianluca Cecchi]

I have a samba pdc.
I would like to automatically assign at next logon a disk share with a
particular letter that is the same for a group of users (such as L:\).
How can I see with samba and/or windows tools what are currently the disk
labels used by this group of users so that I can choose accordingly?
And in general, is there any smb.conf or other config option that lets me
set a unique disk letter for a share, so that I have users accessing
consistently the different disk shares?

thanks in advance,
gianluca