You wouldn't do this in the user accounts. I assume that you have your users authenticating in some form. If you've got then, then the best option is to setup the appropriate policies to do that.
There are articles in the Knowledge Base that deals with setting up different kinds of policies.
http://support.qbik.com/index.php?_a=kn ... ubcat&_i=2
You can also refer to the helpfile, which has good instructions on configuring different policies.