You have several options here.
One) as was suggested, you can put the hub on a long ethernet cable if that works for you.
Two) if you happen to have an Aeon minimote, this can both include and exclude zwave devices to your smartthings network, so that’s often the easiest way. If you don’t have one, they are typically available for about $25 if you shop around. They are very popular in the community as they can also be used as a button controller with zwave devices, zigbee devices, to change modes, to run routines, etc.
if the devices happen to be zwave plus (the newest generation of zwave) and they are within one hop of another Z wave plus device, they can probably be added in place even though they are more than one hop from the hub. But this will not work with older Z wave devices or with secure devices like locks.
or you can do what we call a “bench pairing.” You bring the device to the hub, pair it there, move it back to where you actually want it to be, and then run a “Z wave repair utility” from the hub, and each device will update its neighbor tables. A lot of people do this when they get a new device, but of course it’s more awkward to do with things like light switches.
So all four of those are possibilities depending on the exact devices involved and whether you already own a minimote.