Using environment specific URLs in $ref

Is it possible to factor out environment specific URLs in $ref.

Example:

The schema definition for a user sits on a server, which has different URLs in different environments.

In the prod environment I would use the prod url of the server serving the schema

• schema:
  • $ref: 'http://schemas.company.com/user

In my local dev environment I would use a local server serving the schema

schema:

• $ref: 'http://localhost:8000/user