Can I have a separate inventory than what I normally sell?

Is there a way to add products separately than what I already have? I also have a couple other domain names that having a store with inventory under one of those could be ideal as well. All of my domains now point back to my original store.

I hand stamp jewelry and custom gifts but recently acquired vintage and fragile items that I would like to list to keep track of everything to sell mainly locally. Crystal, stemware, lamps, mirrors, things I really do not want to ship.

But how can I do this the best way?

Just don’t publish them to the online sales channel if all your doing is managing the inventory manually in one place.

If you want the inventory to be automatic as part of orders and you don’t care that customers go from site A to your main sites checkout domain name then use buy buttons on those external sites.

https://help.shopify.com/en/manual/online-sales-channels/buy-button

Beyond that you’d have to get into much more detail and effort of the individual businesses.