Redirect order form thank you pages based on gateway used

Ontrapages now gives us the ability to create order forms with a credit card option and a paypal standard option on the same form: 

This template for example: https://snag.gy/OS93xa.jpg

However, upsells are not compatible with paypal standard. 

Therefore there needs to be a solution that allows us to redirect to one page when CC was used, and another page when PayPal was used.

Otherwise, the above Ontrapage template will never be compatible with using upsells.