COA to multiple NAS

Hi I've got a scenario where we have multiple NAS devices authenticating their clients via a freeradius server. I want to originate COA requests to the NAS devices from the radius server and I have succeeded for one device by making an entry for a specific NAS in the home-server section of originate-coa. We add and remove NAS devices quite often and don't want to have to reconfigure originate-coa and restart freeradius every time. How we can enable dynamic addition of NAS to send COA requests OR can we send COA to servers without preconfiguring? Currently using & testing Freeradius 2.2.6 but in the process of migrating to 3, latest.