For a configuration like this we recommend creating two separate apps. When an app is deployed, we pull, build, and deploy the latest commit for each component. If one-component fails to build or deploy, all components rollback to the last successful deployment. Running production and staging in the same application might be possible, but would certainly blur lines between staging and production.

As a separate matter, routing between components in the same app is currently only based on path. All domains within the app will be routed the same. Service components can examine the Host header to distinct actions based on hostname, but routing based on distinct domains within an app is not currently possible. We are examining this as a feature.