Wordpress formidable forms plugin - change in code

I am using the Formidable Form Pro plugin for a job post form.

I have added a "Register User" action in the form using: https://formidableforms.com/knowledgebase/using-add-form-actions/.

On first time, the job is being posted and user is being registered, but the next time the user wants to create the job, they get "email is already registered" issue.

I want to prevent this error and make the job post linking it with existing user if email is pre-existing. I am not able to do this using Conditional Logic provided actions in form action. Is there any built-in way to resolve this in Formidable or any plugin that adds this functionality. Here is the gist of it:

If email is not registered then new user should be created and job should be linked with him. (Already being done).
If email is registered then new user registration should not be attempted and the job should be linked with existing user. (Facing issue in this).