Sending my prayers that Josie heals up just fine.
This is one of my biggest fears, that my large bird will someday (in a moment of inattentiveness) hurt one of my smaller birds. It could happen to anyone of us. Don't fret too much, just keep praying that everyone will come out OK. That's the most important thing.
I now have my big and littler ones in separate rooms. I know things could still happen, but it's better than them rooming together.
With Target flying into another room, I guess where they live does't really matter much! Maybe the littles in a room with a door that you can close while target flies about?