I'm trying to determine if it's possible to have two different Visualforce login pages so that some external apps use one Visualforce page to authenticate users, while others use a different page. I have a need to add custom branding/messaging for users signing in from a specific external app.
In the OAuth Web Server flow documentation I don't see any parameters that can be added to the Authorize URL that would target a specific page. As far as I can tell the hostname in the authenticate URL is the only aspect of the URL that determines what page a user is sent to for signing in.
I would like to avoid setting up an entirely new community simply to host one login page with custom branding.