Yes, you can have more than one hub per smartthings location. For example, quite a few people have a Samsung television acting as a hub plus a standalone hub for Z wave plus a smartthings station as a charging station. Whenever you add a new zigbee device, you will have to specify which hub you want it attached to, but you can include devices from multiple hubs in the same routine, although it does mean that that routine will run in the smartthings cloud rather than running locally.
Samsung did recently add a new utility to allow you to migrate from one hub to another in the same location.
At present, it is an all or nothing migration. You can’t pick and choose which devices to migrate. And at the end of the migration, the original hub will be reset. So I don’t know if that’s what you want to do or not. I think I would probably just try adding one device to the second hub (rather than using the migration utility) just to see how it goes. If your hub is going on and off continually, the migration utility might not work at all.