Commission based on payment method

hi,
I want to know how to calculate the admin commission based on the payment method.

I have Cash on delivery, Direct bank transfer which is offline payment method. But if customer choose these method for payment, the system still counted this as commission which is not make sense, because the money is directly goto the vendor instead of me.

So, I want to know is there any way to calculate the commission only when the customer use online payment method that go through the admin account, eg stripe.