Use same REST binding for any operation in OSB 12C

Question

I am trying to call a 3rd party REST service from OSB 12C using the REST adapter in the External Service. This service has a single endpoint for multiple operations which are differentiated using the JSON payload. URL: http://3rd.party.com/product/price

Example:

{
  "method": "getprice",
  "item": "12345"
}

The response would fetch the price of the item.

On the other hand:

{
  "method": "setprice",
  "item": "12345",
  "amount": 123.50
}

would set the price.

I was planning on exposing two services: http://my.osb.com/price/getprice?id=123 and http://my.osb.com/price/setprice?id=123&price=123.50 They would share a common pipeline to convert the request and response payloads.

However, the REST business service requires binding to an operation. Two proxy services would have two operations. So, what value would I give in the Method option in the business service's adapter so that a single resource path would be used by all methods/operations?