Thats a very good idea,i think you should talk with the people in charge.if you need any other relationship advice am here.
Typically I use Dun & Bradstreet (https://www.dnb.com/) for vendor or customer credit lookup. They have good customer service and very accurate information.
Setup your business as a pass through. You run the transactions + charge a fee. Likely, for the businesses you mention, they'd be happy to pay a premium fee... as you will be the only payment processor to accept their transactions.
Its a combination of the First Data Offerwise Platform and the CardSpring API. You need to get certified by First Data in order to get access to the datasets required to build a service like that.