Help playing multiple custom sounds notification to IOS phone

I built an automation to welcome my gf home and also unlock the front door. While the automation works fine, I would also like to use the IOS sounds and play two of them to her phone. I can get one working just fine but when I try to get two of them to play, they both play at the same time. What do I need to do to get them to play one after the other?

  action:
  - service: notify.mobile_app_user1_iphone
    data:
      message: Welcome Home
      data:
        push:
          sound: US-EN-Alexa-Welcome-Home.wav
   mode: single