Page Redirect Protection

I am looking for some advice/assistance on how to do the following process.

First, a user completes a gravity form. (I can get this part)
Next, after form submission, the user is redirected to a protected page that is only accessible upon referral from the current page or only accessible from the referral of the gravity form.

OR

I would like the for the gravity form, after submission, to execute a shortcode on the same page.

Here is what I am trying to do:

I want to make a gravity form act as a contract that is required to be complete before continuing on to another part of a listing process. The person must complete the form before they can move on to the next non-gravity form form. The non-gravity form form is available via a shortcode from another plugin.

Any ideas? Thanks in advance.

Awesome. It almost works. One last issue. The "protected form" that is displayed via the short code is a two part form that appears to use jquery/java. Once gravity form is submitted, it returns the protected form perfectly.

However, once I input the the data into the protected form and push next, it fails and reloads the gravity form.

Any way around this new issue? The form is the "place an ad" from the plugin Another Wordpress Classifieds Plugin.

Thanks in advance.