wildcard matching on username?

[Jiann-Ming Su]

I'm running freeradius 2.1.8 with a MySQL backend.  I'm want to do MAC based authentication for network access control on my switch.  Is it possible to specify a wildcard for the username (mac address)?  That is, if I have a bunch of computers with the same OUI on the NIC's, how do I configure freeradius to just match on the OUI without adding each MAC address as a user?  Thanks for any tips and insights.