Security role for taking credit card payments

I would like to know if there is a role or a workaround that will allow a user to take only credit card payments. I was going to try to use the Billing Portal for internal use as well for taking payments, but apparently Oracle does not allow that functionality internally. Only external customers can set up the credit card payments. Is there any functionality or role that would allow us to have our customer service group take a credit card payment without having access to anything else in AR?
I would like the ability to have an internal user to be able to enter credit card information into the client portal, the same a when a customer is logged into the client portal. What security would be needed to allow this? We don't want to give them full access to CC information