ORDS, SODA & JSON in the Database

I was wondering if a REST service can be created for multiple tables. For example, I have 2 tables - PROJECTS and PROJECT_BIDS. Could a REST service be created that is expecting a JSON payload that looks something like this:

{"PROJECT":"Project1",
 "PROJECT_BID":[{"PROJECT":"Project1",
                 "BID":"Bid1"
                },
                {"PROJECT":"Project1",
                 "BID":"Bid2"
                }
               ]
}

Is it possible to create a REST service that would MERGE the data directly into the 2 tables, in case the data already exists in the tables? I hope this makes sense.

Thanks,

Dan