You wouldn't know what transactions occurred, and 1% of a company's revenue is not a reasonable payment for doing nothing but saving time copying-and-pasting implementation scripts from the individual payment sites.

If you meant that this site should somehow provide a payment button for all those providers without even opening an account with them, that's not a problem you can solve with technology. Know-your-customer banking laws and factoring clauses in merchant agreements mean you can never create that service.