Add a third flow to payment gateway where the button on "Payment Information" change to Paypal when selected

Hello, we are trying to find ways to simplify the checkout flow on a site already using commerce_paypal, and it would be good if we could reduce the steps in the checkout flow. One idea we have is that if you choose Paypal on "Payment Information" it could replace the payment button with the paypal one using javascript.

Assuming this isn't already possible (I couldn't find a setting which would allow me to do this)., what would be the preferred approach to developing this as an option (if at all viable).

We may have time to look into this further down the road, so understanding a preferred approach would be great, then we can develop and share a feature branch back when we have time.

Thanks for your time,
Dan