Being able to configure flavors repositories

I have a use-case where the repositories for flavors should not be the same than repositories for extensions.

Basically, the UI for Create Wiki will call FlavorManager#search(), and only some repositories should be enabled (where flavors are moderated).

But if I go to the standard UI (Extension Manager in the Administration), I should be able to search for extensions on the standard repositories.

So I need an equivalent of ExtensionRepositoryManager for flavors, which should be configurable (at least in xwiki.properties).