Possibility to configure the sign in flow to send user to external service directly

Currently the sign in goes always either through the sign in page or the popup. We have one instance which we have integrated to an external login service that provides all the different login possibilities for the service (Google, Facebook, etc.) in that service. Therefore, the users select their login method once they are forwarded to the login service. Now, after clicking the "Sign in" button, the users still have to click the "Sign in with X" which is the service to sign in. We have received feedback that this is not the optimal way as many users would expect to be directly redirected to the sign in service. Now they have to click ”Sign in” twice + select the service. We feel this should be configurable some way, so in case a configuration flag is set, the users are redirected directly to the first available OmniAuth login method. The service’s own sign in URL would still be accessible but just the functionality of the sign in links/buttons would change for the end users.