Hi! I’m afraid this is not possible using Lock (the login widget) as of now.
You can, however, build your own user interface prompting the user for username/password and decide which connection to use based on the
domain/username syntax. Once you have the username, password and connection figured out based on user input, you can use Auth0.js to send the credentials to Auth0 for verification.
When editing the hosted login page, there is a “Custom Login Form” template that uses Auth0.js, that you can use as a start model. Building your own login form can be complicated, especially if you need to account for signup, socials connections, password reset and all the flows that are managed by Auth0. But if you just want AD connections with a single username/password form, this might work for you.
You can also describe this feature request in https://auth0.com/feedback for the Product team to consider for future versions.