pam_eaccess is a PAM module which add a generic way to do authorization. Indeed, for each service (for which you want add authorization) you can define the list of users (or all) who are allowed to connect to this service.

# svn co http://svn.asyd.net/svn/pam_eaccess/tags/20051106 pam_eaccess
# autoconf
# ./configure
# make
# make install

Check if you have the /lib/security/pam_eaccess.o