LB layer - Issue with shared secret.

Hi all, I would like to use a load balance as the first layer proxy the requests on more than one radius server. In this way, the radius packet will always be sent from the same IP address, so we would have a problem with the shared secret. Can I do that freeradius retrieves client's information via NAS-IP-Address attribute and not via Sender IP Address? I use freeradius-server-3.0.15 on RHEL 7. Best regards Andrea