Adding a per transaction fee to the Event + plugin for Client usage

I am looking to add Events + to a client's website to maintain an upcoming event using paypal. We are in need of creating our own charge per transaction. Is there a way to charge a percentage or flat fee that is directed to our paypal or merchant account with the remainder to be distributed to the client's paypal account (minus Paypal's processing fees)?

Thank you,

Marie Daniels