Restricting ssh access to internet but not to internal network

["Patrick" <p_rynhart@hotmail.com>]

I have an server running sshd on Sarge. I want all users to be able to
access the computer from within the internal network - but restrict
access from the internet (to users in a particular group). Can this be
achieved by combining the /etc/hosts.allow or /etc/hosts.deny files and
the AllowGroup (or AllowUsers) options in sshd configuration file.

If so, how ?