[gdm-list] limiting access

[Yan Seiner <yan seiner com>]

I have a machine with multiple logins.

I need to automatically logout all users at a specific time during the
day, and then deny logins until a specific time.

So:

at 7:55 AM all user sessions are terminated, preferrably with some
warning
from 7:55 AM to 8:30 AM gdm displays a message that user logins are not
permitted
at 8:30 AM normal login sessions are allowed

How do I go about doing this?