HI, I was wondering if its posible to build an app on top of the ethereum blockchain, that runs smart contracts based on information out of the platform.( another web,domain....) for two parties but both  of the parties just see FIAT currency,  and of course integrate to write a smart contract as easy as posible (not code)all of this  with a central admin (me)  that keep a % of the trade . Im building a marketing app and i want to use smart contracts to simplify transactions and maximize revenue. Building own token?
Using ethereum below the counter (the merchants and clients just see fiat or BTC)?
IF you have any advice  or want me to explain you more i will be more than happy. Thanks