How to produce a dynamic JSON by JSONObject in Java

Question

I need to implement a Java method to return a JSON. Here is the desired JSON output that I need to produce.

{
  "channel": "channelId",
  "thread_ts": "threadId",
  "reply_broadcast": true,
  "attachments": [{
    "color": "#2F8AB7",
    "blocks": [{
        "type": "divider"
      },
      {
        "type": "section",
        "text": {
          "type": "mrkdwn",
          "text": "Test header text"
        }
      },
      {
        "type": "divider"
      },
      {
        "type": "section",
        "text": {
          "type": "mrkdwn",
          "text": "Test text 01"
        },
        "accessory": {
          "type": "button",
          "text": {
            "type": "plain_text",
            "text": "Click Here",
            "emoji": true
          },
          "url": "https://mycompany.com/link1"
        }
      },
      {
        "type": "section",
        "text": {
          "type": "mrkdwn",
          "text": "Test text 02"
        },
        "accessory": {
          "type": "button",
          "text": {
            "type": "plain_text",
            "text": "Click Here",
            "emoji": true
          },
          "url": "https://mycompany.com/link2"
        }
      }
    ]
  }]
}

For this aim, I've used JSONObject and JSONArray (org.json). Here is the particular section of this JSON which must be dynamic and extendable.

{
  "type":"section",
  "text":{
    "type":"mrkdwn",
    "text":"Test text 03"
  },
  "accessory":{
    "type":"button",
    "text":{
      "type":"plain_text",
      "text":"Click Here",
      "emoji":true
    },
    "url":"https://mycompany.com/link3"
  }
}

The problem is, merging/appending two JSONObjects together is not possible without defining the 'key'. How can I add the dynamic part to the JSON.

private JSONObject produceJsonBlock(final List<String> links) {
    JSONObject jsonObject = new JSONObject()
            .put("channel", "channelId")
            .put("thread_ts", "threadId")
            .put("reply_broadcast", "broadcast")
            .put("attachments", new JSONArray()
                    .put(0, new JSONObject()
                            .put("color", "colorMessage")
                            .put("blocks", new JSONArray()
                                    .put(0, new JSONObject()
                                            .put("type", "divider")
                                            .put("type", "section")
                                            .put("text", new JSONObject()
                                                    .put("type", "mrkdwn")
                                                    .put("text", "")
                                            )
                                            .put("type", "divider")
                                    )
                            )
                    )
            )

    links.each { final String link ->
        JSONObject linksJson = new JSONObject()
                .put("type", "section")
                .put("text", new JSONObject()
                        .put("type", "mrkdwn")
                        .put("text", "Test text ...")
                )
                .put("accessory", new JSONObject()
                        .put("type", "button")
                        .put("text", "Click Here")
                        .put("emoji", true)
                        .put("url", "https://mycompany.com/${link}")
                )
        /**
         * ???
         * As I checked jsonObject.append()/jsonObject.put(), they cannot be used. because
         * they don't accept just a JSONObject without introducing the key.
         * */

    }
}