authorize.net batch CREDIT

Has anyone implemented a batch CREDIT post to authoirze.net which is initiated in the admin area. We are looking to create a process for refunding a product (a show in this custoemr's case) for all the customers who have purchsed it, in the case that the show cancels. The trick is that the customer will want to keep the transaction fee, so we want to be able to refund for tickets only.

We will be writing this - it may end up just creating a report and then it would be run by a batch job. If anyone has done something like this - please point it out, it would be helpful.

thanks