Free UPS Ground to specific customers only

I need a way to be able to provide free UPS Ground shipping to specific customers, of my choosing, so that they receive it on every order no matter the amount or products ordered. After searching for a while, there is no way to do this through Shopify or an app. Here’s my question; can a developer create a simple check box on a customer’s profile that I can check so that the customer then gets free ground shipping when ordering online? This would be an ideal Shopify update.

If anyone knows or can find me someone who does, it would be greatly appreciated. I have been trying to solve this issue for 4 years!

Thank you