Change Music sync playlist
I want to change the Music playlist synched to Apple Watch to another playlist I created in Music/iTunes. The Apple Watch App on the iPhone 6 only provides 2 default playlists "Music Videos" and "Purchased". How can I add another playlist to be synched to the Watch. I run and don't always carry my iPhone and want to be able to have music stream from the Apple Watch to Bluetooth headphones.
iPad Air, iOS 8.0.2