Custom Conditional Registration Form

I need to collect some custom member fields that are different based on the type of user registering on the site.

Gravity Forms has this conditional form capability and I can create the forms and flows I need, but don’t know how to “hook” it into the responsive directory framework to replace the builtin (RD) registration process.

Is there a Hook or Filter that I can utilize?

Can I copy a file to the child theme and redirect somehow?

Any suggestions?

Thanks