Is it possible to sync. smb usernames to unix username ?

[Frank Wiegerinck (Faculteit)]

Is it possible to sync. smb usernames to unix usernames.
I have to implement a Samba-server into network where
users already have an unix username. There are already
2000 users and adding these usernames manual isn't 
possible because it will take to much time. Each year
400-600 users have to be deleted and the same count of 
users have to be added to the unix-environment and
samba-environment. A option or programma which will
sync. the userdatabases will be nice.

Thanks in advance,

Frank Wiegerinck