Your Zwave devices DNI # is joined to the zwave radio (inside the hub). There are ways to migrate devices to a new hub with somewhat of a minimal process you can read up on it here Restoring a backup to a new hub
However just to fair warn you....I just completed 2 weeks of testing at which I completely removed all my zwave devices from being paired to the internal radio, and paired them all to the Y-cable attached zwave usbstick radio. Worked great for about 2 days, then every thing started failing, especially after rebooting the hub. So YMMV with that experience if you have to go that route.
Just one more reason i've been intentionally transitioning my devices from zwave to zigbee as for me it has been far more reliable, on these hubs.