Modify existing integrations in api-gateway resources using serverless

I have an existing api-gateway that is deployed with certain resources:

GET /test/{id}
POST /test/{id}

These have MOCK integrations currently, and I am wondering if it is possible to modify these to using lambdas we have in a serverless project?

I have tried, but so far it does not seem possible, I always end up getting the Another resource with the same parent already has this name: {id} error.

I am attempting to modify like this:

    name: MyPythonGetJob
    description: "access GET endpoint"
    handler: src/my_get_endpoint.handler
      - http:
          path: /test/{id}
          method: GET
          private: true

Is there a function argument or something that can tell serverless I want to modify an existing resource?