How to ignore some NASs?

Hi, I need to configure freeradius to ignore requests from particular clients based on NAS-IP-Address. Is there a quick way to do this? Thanks, Leighton --- This transmission is confidential and may be legally privileged. If you receive it in error, please notify us immediately by e-mail and remove it from your system. If the content of this e-mail does not relate to the business of the University of Huddersfield, then we do not endorse it and will accept no liability.