We are integrating into our Drupal site modules to allow customers to checkout using either of the following choices: Amazon, PayPal & Dwolla. As all three allow payment to multiple parties during the checkout process (Amazon Flexible Payment System, PayPal X and Dwolla's Faciliator. While their are Drupal 7 modules, we need to customize with each API to provide the solution. Buyers can select to pay using PayPal, Amazon or Dwolla. During checkout our company, CheckSavvy needs to collect the facilitator fee out of the seller's net proceeds. The bulk of the money goes the online sellers. If a the seller doesn't have the corresponding account with PayPal, Amazon or Dwolla, the transaction pays our company and our company pays the seller via Dwolla less our facilitator fee and $.25 Dwolla charge. Verifying a bank account may also be required.