将响应传递给顺序请求（HTTP_GET-> HTTP_POST）

I have a microservice which outputs following as a response. It's an HTTP_GET request which serves on http://localhost:8050/location?company=5

curl -X GET http://localhost:8050/location?company=5

{
    "locations": [
        { "key": "1050", "lat": 24.000000000, "lon": 46.000000000 },
        { "key": "1254", "lat": 24.999999999, "lon": 46.999999999 }
    ]
}

And I also have a HTTP_POST request, which accepts list of keys and returns relevent branch details. it serves on http://localhost:8060/branches and accepts a json array.

curl -X POST http://localhost:8060/branches -H 'Content-Type: application/json' -d '["1050","1254"]'

and the output would be

{
    "branches": [
        { "key": "1050", "branch_name": "DC", "telephone": "+1 11 111 111" },
        { "key": "1254", "branch_name": "LA", "telephone": "+1 22 222 222" }
    ]
}

and I need the final merged output as following

{
    "branches": [
        { "key": "1050", "branch_name": "DC", "telephone": "+1 11 111 111" },
        { "key": "1254", "branch_name": "LA", "telephone": "+1 22 222 222" }
    ],
    "locations": [
        { "key": "1050", "lat": 24.000000000, "lon": 46.000000000 },
        { "key": "1254", "lat": 24.999999999, "lon": 46.999999999 }
    ]
}

I'm developing an api gateway using krakend and it'll do the above and serves on http://localhost:8080/findBranches?company=2
Here is my krakend-config.json

{
    "version": 2,
    "extra_config": {},
    "timeout": "3000ms",
    "cache_ttl": "300s",
    "output_encoding": "json",
    "name": "sample",
    "endpoints": [
      {
        "endpoint": "/findBranches",
        "method": "GET",
        "extra_config": {
          "github.com/devopsfaith/krakend/proxy": {
            "sequential": true
          }
        },
        "headers_to_pass": [ "*" ],
        "querystring_params": [ "company" ],
        "output_encoding": "json",
        "concurrent_calls": 1,
        "backend": [
          {
            "url_pattern": "/location",
            "encoding": "json",
            "method": "GET",
            "host": [ "http://localhost:8050" ],
            "disable_host_sanitize": true
          },
          {
            "url_pattern": "/branches",
            "encoding": "json",
            "method": "POST",
            "host": [ "http://localhost:8060" ],
            "disable_host_sanitize": false
          }
        ]
      }
    ]
}

How do I manipulate the response of 1st backend and send it to the post request of the second?