myweb:
  extends:
    file: specify-file-as-self.yml
    service: web
  environment:
    - "BAR=1"
web:
  extends:
    file: specify-file-as-self.yml
    service: otherweb
  image: busybox
  environment:
    - "BAZ=3"
otherweb:
  image: busybox
  environment:
    - "YEP=1"