Dynamic Success Landing Page

Hey there! We want to provide a different coupon code to contacts based on where they came from (referring url) after a form submission - ie LinkedIn, Facebook, Community, etc. 

We have utms setup to capture the referrer upon form submit. I've setup the segmentation, a snippet, the dynamic content with the different coupon codes, and put that on a success page. The form is setup to follow up with the success page once the form is filled out. The issue is, the processes to update the segmentation are slower than the follow-up page is served and therefore the contact gets the wrong coupon code.

Is there another way to provide the code dynamically upon form fill outside of the segmentation / snippet way without sending an email?