Prevent login until user role is assigned

[orizzontiholding]

Your plugin is very nice and configurable. I have just a question about user registration.
I've restricted the allowed domains that can use the SSO process to login, but I need to assign user roles, I have some custom roles and I want to have the ability to assign the roles to the users when needed. Is there any way to achive this before the users are added to the wp database?