We are using sentry relay in staging and production environments and would like to have one sentry project for both of them.

This could be done by adding an environment field to the sentry config section:

    relay:
      mode: proxy
      port: 8080
    sentry: 
      enabled: true
      dsn: https://...@....ingest.sentry.io/...
      environment: staging

Then we could switch between environments with sentry website UI: