SAMBA vs. NT :Logon To

[Andres Punning]

Dear sirs,

I would like to migrate from NT PDC to SAMBA.
I have a lot of Win95 workstations, NT 4.0 PDC
and some SAMBA file servers.

My NT  PDC allows to configure users:
User may log on to all workstations,
or
User may log on to these workstations: (up to 8)

How can it be done on SAMBA?
Is it possible to check some variable substitutions
(%g, %U, %m, %M, ...) before normal password
validation and in some conditions return "wrong password" ?

regards,
Andres Punning