When two sisters go to war, no one wins.
Except for the sister who wins, but that's just a coincidence.

the many songs were

I Will Always Love You by Whitney Houston (originally by Dolly Parton) https://www.youtube.com/watch?v=3JWTaaS7LdU
Running by Evermore https://www.youtube.com/watch?v=jQlRwiSLTQY
Sweetest Thing by U2 https://www.youtube.com/watch?v=5WybiA263bw