Gustav Mahler's stirring Eighth Symphony is more than just a symphony. It's a massive orchestral work, but it's also an ambitious choral opus about the transformational nature of love. It will take a large village to present this piece, and conductor Gustavo Dudamel will lead L.A. Philharmonic as well as the combined voices of four separate choirs — L.A. Master Chorale, Pacific Chorale, L.A. Children's Chorus and The National Children's Chorus — at Disney Hall.