Using CMS to create user login


I’m trying to create some kind of system where my client can use the Webflow editor CMS to create new login data for their clients. This data contains an email, a password, and a dropdown where they can select either ‘page 1’ or ‘page 2’. Users can’t sign up, they can only log in using the data my client created. Also, depending on if my client selects ‘page 1’ or ‘page 2’, the user is redirected to this page after the login.

I’ve tried using Memberstack for the login, but I can’t get rid of the sign-up form. Also, if using Memberstack, I can’t find a way to link it with the website’s CMS (so you can use CMS to create the data).

Is this possible? And if yes, how? Thanks!