Multiple Merchant Services Rates

In MN we can only charge a convenience fee equal to what our payment processor charges us. At the moment in-person (DSP terminal) and online payments (DDP Merch Services) are set to the same % rate (2.9%). Could you create a way for us to charge different rates for terminal transactions and Portal Transactions?
Thank you!
Abbie Montermini
NorthEast Dance Center

abbie@nedancecenter.com