How to send multiple JSON in single request(Jmeter)

Though I could see this question might be repeated but couldn't find any similar solution for the below JSON strut. Pls suggest.

I have excel sheet where the data's in columns look like : CSV file data

My expected JSON as:

       {
       "Child ": {
       "10"
          : { "Post": { "Kid-R":1 },
        "Var": [1,1 ],
        "Tar": [2,2],
        "Fur": [3,3]},

       "11": 
          {"Post": {"Kid-R":2 },
          "Var": [1,1 ],
          "Tar": [2,2 ],
          "Fur": [5,4 ]}
          },
         "Clone": [],
         "Birth": 2,
         "TT": 11,
         "Clock": ${__time(/1000,)}
           }

I have tried incorporating beanshell preprocessor in JMeter & tried below code:

    def builder = new groovy.json.JsonBuilder()
    @groovy.transform.Immutable
    class Child {
    String post
    String var
    String Tar
    String Fur
    }


    def villas = new File("Audit_27.csv")
    .readLines()
    .collect { line ->
        new child (line.split(",")[1],(line.split(",") 
    [2]+","+line.split(",")[3]),(line.split(",")[4]+","+line.split(",") 
   [5]),(line.split(",")[6]+","+line.split(",")[7]))}     

    builder(

    Child :villas.collect(),
         "Clone": [],
         "Birth": 2,
         "TT": 11,
         "Clock": ${__time(/1000,)}

    )
     log.info(builder.toPrettyString())
     vars.put("payload", builder.toPrettyString())

And I could see below response only:

Note: I dont know how to declare "Key" value (line.split(",")[0]) in the above solution.

      {
     "Child": [
      {
        "post": "\"\"\"Kid-R\"\":1\"",
        "var": "\"[2,2]\"",
        "Tar": "\"[1,1]\"",
        "Fur": "\"[3,3]\""
    },
    {
        "post": "\"\"\"Kid-R\"\":2\"",
        "var": "\"[2,2]\"",
        "Tar": "\"[1,1]\"",
        "Fur": "\"[3,3]\""
      }
     ],
     "Clone": [],
     "Birth": 2,
     "TT": 11,
     "CLock": 1585219797
      }

Any help would be greatly appreciated

Solution

Actually I am gonna follow DmirtiT suggestions, as mentioned in some of post to use random variable for bulk API request. Same answer it helped me here as well to generate multiple JSON structure with unique data. Thanks..