Feature Request: Checkbox Payment Field in Wix Forms

I’ve run into an issue with one of my clients: instead of a single-choice-required radio button Payment element in a Wix Form, I need users to be able to select multiple choices from a checkbox field & then have the form/checkout do the math on how much they need to pay.

i.e. for an art show registration, a user wants to submit an art piece to the photography category ($15 per entry) AND the juried show category ($16) > instead of having to make additional options to accommodate combinations