We have a website where we group 22 language variants under the en-US primary page. But there are technically multiple primary languages. So having the ability to make subgroups of languages would help tap into the fallback language options.
The primary language for a group becomes the fallback for all languages. If you land on a page missing that language then it will go to the primary. But we may have several languages that are associated and we'd like to select a primary for that group.
For example: fr-FR (primary for this set of language regions) fr-BE fr-CH
So if fr-CH is missing, Id like it to fallback to fr-FR but still have it in the larger associated group of language page variants.
