Choose idp based on email domain

[Frank]

Hey, 

Right now we have CAS 6.1.5 which uses jdbc to login and retrieve user information. We want to expand this with saml idp. 

Instead of clicking on the right idp from a list, we want cas to dynamically choose the idp based on the domain of the email which we use for the login page. We probably have to split the login page. First page will have one input field where the user will have to fill in their email address and press next. After pressing next CAS should be able to process this email address and find the correct idp and redirect the user or it should fallback to showing an input field for a password and use the username+credential (and jdbc) login method. 

I have been looking into the documentation and blogs but have only found solutions where users have to select the right idp from a list. Is this something CAS is able to do with using configs or should we look in to extending the flows?

Kind regards,

Frank