This depends on what RADIUS Server you are using. For instance, the RADIUS
TACACS Server for Windows (downloadable from http://www.hkstar.com/~unet/)
has a feature of limiting the number of concurrent logins by username (or by
group).
Regards
+-----------------------------------------------------------+
+ Developer of Windows based Security Server +
+ +
+ TACACS, XTACACS, TACACS+ and Radius +
+ +
+ Peter Mak +
+ Universal Networks Company Limited +
+ unet@mailhub.hkstar.com +
+ http://www.hkstar.com/~unet/ +
+-----------------------------------------------------------+