This sounds very similar to what we'd recommend for the Joomla language manager. Have you setup an Object for each language category you have? If not, please enable the Open Graph - Content plugin and set that up. Then, you should be able to setup the Channels appropriately for each language object/category you have.Each language has it's own category in com_content. And a category has an opengraph object which is linked to the Facebook channel for the specific language
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