I have offline and card payments enabled on my form and everything works great.

I have a few discount codes set to 100% discount, i.e. when the user types in the code, the Total field value turns to 0.00, so also great.

I would like to have more control over what is displayed to the user:

The discount codes are given to specific people and when they fill in the form and are forced with validation to choose a payment option, they get confused (since they have 100% discount they don't like having to select a payment option). I do not want anyone else to be aware that some people are receiving 100% discount, so I do not want to display a message saying "select offline payment if you have a 100% discount code" or change the offline option label to something like "Offline Payment / Payment not applicable"

Ideally, I would like the payment option field to be hidden as soon as the 100% discount code is entered/Total field value changes to 0.00
or
as soon as the Total field value changes to 0.00, the payment option value should be forced to default to Offline.

Can anyone help me on how to do either of these?

Any suggestions?

Thank you