How to configure the login url when using the Device Authorization Flow

I’m trying to set up the “Device Authorization Flow” to allow users to authenticate to Auth0 on headless systems, i.e. amazon ec2 servers. I have many different SAML/SSO connections configured in my Auth0 account and I need to be able to use a specific connection when the user is logging in.

For normal web based authentication use cases, I have set up my Universal Login Page with a handler that expects a url like this:{auth0_connection_name}

The page knows which Auth0 connection to use when authenticating by examining the url itself.

The device authorization flow defaults to logging in via this url however:

Is there some hook or rule that I can create that configures which sign-on url is used for logging the user in via the device authorization flow?

One solution that would be great is if it were possible to pass connection={auth0_connection_name} as a parameter to the /activate endpoint that is part of the device authorization flow. This would ideally behave similarly to the /authorize endpoint, which accepts a connection parameter and uses that to determine how to have the user login.