Authorize with SQL and not authenticate

Hi people, I've just have a default file with a LDAP + SQL queries for user authorization, and NTLM for user authentication. Also I want to just authorize hosts sending its MAC Addresses as its usernames according to a SQL query matching a Mac Address table, but I don't want to authenticate them because the Active Directory doesn't contain MAC Addresses as usernames. Is it possible just authorize with Freeradius and so let hosts to access the LAN network ? Thanks a lot!!!