Drupal Developer - Custom Module Development

Seeking a Drupal developer who will be able to develop a custom 'Drupal Commerce' module. Must have strong knowledge of the Drupal API/Best practices, and experienced in creating custom modules; we are not simply looking for a PHP hack. The custom module that we require will be able to trigger a payment from a Drupal user's PayPal account to another PayPal account (not related to a Drupal user). The target PayPal account will vary depending on the user's profile, and the number of PayPal accounts must be allowed to dynamically grow/change. We envision the site to be based on Drupal groups, so that each authenticated user would have their own 'mini-site', therefore, previous knowledge of Drupal Groups is a plus, though we are open to alternatives. A more detailed scope will come from the site builder before the work starts.