login w2k server by time

[nospam <nospam () dranem org>]

Is there a way to limit when any user/groups may login to a server based 
upon time?
and wait until a manager comes to each station to authorize network 
access to that Server [Win2000]
[workgroup setting] no domain setup   [winXP clients] [1 win98 print server]

I have a friend who wants to limit when a server is accessed to daytime 
hours only
also they want it to be limited to a manager who will provide a password 
when they are allowed to use the server.

Further more they need to use said locked down server during business 
hours for 15 users/PCs
for regular business to access a dental database from a shared folder 
from the windows 2000 server

If this still makes sense how can I help them limit access
1) over night
2) using a master password

suggestions;
good points / bad point / gotchas / etc
ALL welcomed

THANKS    
evets  /   nospam     ;-)