User Mode for SEP 12.1

Hi,

Currently all of my cliens are in computer mode.  I would like to convert a subset of machines to user mode and have different firewalls policies based on who the user is.  Is this a reasonable way to use user mode?  Can I setup a SEP group to use user mode?  If not, how would I convert several machines to user mode?  I am running SEP 12.1 on Windows 7.

Thanks,

Bob