[Help-gnu-radius] clarification on mulitple login

[List User]

Hi,
this is a gist of the issue I have emailed earlier. Sorry for repeat.

I have read 
http://linuxselfhelp.com/gnu/radius/html_chapter/radius_9.html#SEC80 multiple 
times. Would someone please clarify what happens when naslist file DOES NOT 
have IP address/name of the NAS.
It appears that in this case radius DOES NOT enforce Simultaneous-Use limit. 
How can I fix it (i.e. no entry in the naslist file, but still allow only 1 
login).
thanks