Internal + external custom section

Inside my serverless.yml I have an external custom section:

custom: ${file(../../serverless.common.yml):custom}

Is it possible to add local custom settings as well?
Something like this:

  - ${file(../../serverless.common.yml):custom}
  - dotenv:
      path: ../../.env

What happens when you try? Remember, you can serverless print to see what the serverless.yml would look like with all variables added and files inserted.