Can I ask a Gravity Forms question?

I'm not sure if I'm allowed to ask about plugins that aren't in the WPMU family, but this one's about Gravity Forms. If staff can't answer, can someone else with knowledge?

I'd like to allow my multisite subsites to process transactions on their sites and I'd like to be able to keep a portion of the transaction. So if the normal CC fee is 2.9%, I want to keep 2% on top of the CC fee. Does that make sense?

Can I accomplish this with Gravity Forms? Or is there another way?