NAS-port higher than base IP address

[Hillel Seltzer]

Hello,

I have a question regarding the feature to assign the 
Framed-IP-Address with the plus ("+") sign to add a base
address to the NAS port number.  I have a Cisco router
with analog dialin ports that come in on NAS-Ports numbered
higher than the last part of the IP address that we want
to assign.  For example, NAS-Port 70 might be assigned for
IP address xxx.xxx.xxx.65 regardless which of several users 
logs in on that port.  Is there a way to make this assignment
in the users config file?

Thanks.
---Hillel