How can I post products or categories on other websites?

[MHGDesigner]

Hello, I have a group of websites that are related and I don't want to replicate the store for each one.  I'd like to just have the store set up on one and then be able to display products from the primary one on the secondary and tertiary sites.  That way all the transactions are done in one place, in one store, and I only have to maintain one store.  Like for example.  I have cooking sites.  And the main site is XYZCooking.com  Then I have Billy's cookbok.com and Betty's cookbook.com and in the XYZCooking.com site I have the store and in that store there are pots and pans that I want to sell on Billy's and Betty's sites.  How do I do that?  V2.0.22a

[Maxim Pishnyak]

Main web site generate xml stream (import), child web shops eat that stream (export).