Strategy:
Fracture Zombie,Isolate Daka, try to spread the damage across all the Nightsisters to avoid killing any of them unintentionally.
Once Annihilate is ready, Kill MT as she is the main damage dealer and is the main threat to your team. Kill daka first with normal
attacks. Repeat the process again annihilating the rest of the opposition one by one.
If you do kill any of the Nightsisters (non annihilate) isolate zombie and just continue from where you were.