How to embed unlisted product in another site?

I have OpenCart installed to nocturnalfeast.com, & need to sell products on OpenCart there which are unlisted on the storefront there, on funkysalamander.xyz. I want to be able to post the unlisted products on funkysalamander.xyz, and have them only available through that site, so if a user searches for them on nocturnalfeast.com, they won't show up.

Nocturnal Feast will have its own offerings, which will be available & function like a traditional storefront, and I'll have hidden products embedded on Funky Salamander which will direct users to the store to complete their purchase.

How can I make this happen?

Thanks in advance,
-N

I just had the idea that I could maybe have a second store unavailable somehow from the store domain linkking to the other domain? I dunno. Does anyone have clues for me?