Freeradius updating /etc/hosts?

[Dave]

Ive been using freeradius for years to authenticate pppoe users for my 
WISP., Customers get dynamic IP addresses from an IP pool.
Im going to be implementing a new monitoring system, and I need to use 
hostnames to check on customer status.
Anyone have ideas how freeradius can update /etc/hosts so a dns server 
such as dnsmasq can serve the hostnames of customers as their IP changes?