Thing is that only the opposite is possible. Because standards are open anybody can join. When this bridge goes live, you might be followed by Friendica instances over the bridge because the AT Protocol is a true fediverse even if it was designed by a corporate entity and it's first server was a corporate server.
But once that goes live, they also have absolutely no control over it after that. They won't have control or access to your posts between two AT instances unless one of those is the original Bluesky itself.
And because protocols are open, there's nothing that can be done about that... without again limiting reach. Your only option to broadly exclude certain entities from the fediverse is to put the entire fediverse under a central control... but then you're at the whims of whomever controls it and we're back at the same problem as before with Twitter, Facebook, and the like...
@HistoPol @jamie @oliphant @luca @PCOWandre @chronohart @snarfed @m