Proxy IP Address

[Doug Hardie <bc979@lafn.org>]

I have a situation where all my authentication requests are proxied  
to me.  I have 4 different groups of users that require unique local  
polieies and have been using a fairly complicated parsing of the  
Called ID phone number and a couple other fields to figure out which  
group a request is in.  However, I just found out that each of the 4  
groups is being proxied through different proxy servers.  It would be  
real easy to distinguish the group from the IP address that the proxy  
request is being sent from.  However, I have not been able to find a  
variable that contains that information.  Have I missed it?