Do you have a way of sectioning off a portion of your coop and putting the new ones on a roost behind the secured section.
Once they are more used to each other and the new ones have "their" space, you can take the divider down, but leave the roost. Make sure the new roost is not any higher than the ones your birds are currently on.
Once they are more used to each other and the new ones have "their" space, you can take the divider down, but leave the roost. Make sure the new roost is not any higher than the ones your birds are currently on.