With discoverd device you mean endpoint?
What you can do is export 1 device (not endpoint), add every switch in the xml, and re-import the complete xml with all switches.
Other option is to add a device with a subnet, this way you have 1 entry for a complete /24 management subnet, you must use the same radius/tacacs keys, and you cannot filter on source device or specific attributes for a device (only nas-ip).