Excluding non-NAS from simultaneous-use checks

I'm looking for a way to exclude some sources of RADIUS authentication requests from being subjected to the simultaneous-use checks. Basically we use RADIUS for more than just dialin, simultaneous-use is not applicable to these services. I found the following thread on the Cistron mailing list which would solve my problem if I were still running Cistron. http://lists.cistron.nl/pipermail/cistron-radius/2002-June/003861.html Setting the RAS type to none appears to have no effect for FreeRADIUS. Is there another way to accomplish this with FreeRADIUS?