Before I asked questions, I went back and read all your posts on the thread, but I don't see anywhere that tells how old the "new" girls are. There are just two of them, right?
It's normal for new or younger chickens to keep to themselves and not want to eat with or mingle with the older ones. Chickens have strict rules about rank and newcomers usually won't break those rules. That means eating only when the older ones are finished. This is why it's important to make sure newcomers have their own feeding station where they can be sure they can eat without being chased away from the feeder.
If the new chickens are much smaller than the original hens, it's easy to place the food and water inside a safe enclosure with entrances into it that are only large enough for the new ones and not the older girls. For newcomers that are nearly the same size as the originals, you will need numerous feeding stations so everyone has a shot at getting all they need.
This safe enclosure, I like to refer to as a "panic room", is the ideal solution to keeping smaller chickens safe from the bigger ones. You can safely assume the new girls won't be in any danger at night when everyone is interested in roosting. When morning comes, the new girls will be chased out of the coop, and if they have a safe area (panic room) to retreat inside for safety, you won't have to worry about them getting "murdered".
If the newcomers are the same size, or nearly so, then your best bet to insure safety is to have plenty of space and plenty of perches or platforms of varying height so the ones being bullied can find escape. If they free-range mostly, the open spaces virtually assure their safety. If all of the chickens, old and new are going to be penned together in that small run, you may have problems unless the new ones have a panic room to run to.