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Unfortunately, the products in the payment integration cannot be tied on the conditional logic. Unless you'll use the quantity field in your products as the "IF" statement rule.
If you have a complex pricing, you can recreate the products using plain form fields, assign values on them and pass the final price in your payment integration as a custom amount.
Here are the guides that might help:
1. To assign calculation values on drop downs, radio button and check boxes, you can follow this guide: http://www.jotform.com/help/301-How-to-Assign-Calculation-Value
2. To perform form calculations, you can use the form calculation widget as mentioned in this guide: http://www.jotform.com/help/259-How-to-perform-calculation-in-the-form. Or use conditional logic.
3. Now if you have a calculated total price, you can pass it to your payment integration by following this guide: http://www.jotform.com/help/275-How-to-pass-a-calculation-to-a-payment-field
If you need help on setting this up, please let us know.