Newtonsoft Json nested tables in csv umwandeln - C Sharp

{
  "groups": [  
    {
      "id": "111111111",  
      "name": "DummyName",  
      "shared_with": [  
        {
          "userid": "222222221",  
          "name": "Username1",  
          "alias": "",  
          "permissions": "read"  
        }
      ],
      "permissions": "owned"  
    },
    {
      "id": "111111112",  
      "name": "DummyNameZwei",  
      "shared_with": [  
        {
          "userid": "222222221",  
          "name": "Username1",  
          "alias": "",  
          "permissions": "read"  
        },
        {
          "userid": "222222222",  
          "name": "Username2",  
          "permissions": "read"  
        }
      ],
      "permissions": "owned"  
    }
  ]
}

userid	name	alias	permissions	groups_Id

using System;
using System.Xml;
using System.Text;
using Newtonsoft.Json;
using System.Data;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace CreateSession.Helper
{
    public static class jsonToCsv
    {
        public static string getCsv(string jsonString) //jsonString As FormatedJsonString
        {
            XmlNode xml = JsonConvert.DeserializeXmlNode("{records:{record:" + jsonString + "}}");  
            XmlDocument xmldoc = new XmlDocument();
            //Create XmlDoc Object
            xmldoc.LoadXml(xml.InnerXml);
            //Create XML Steam 
            var xmlReader = new XmlNodeReader(xmldoc);
            DataSet dataSet = new DataSet();
            //Load Dataset with Xml
            dataSet.ReadXml(xmlReader);
            //return single table inside of dataset
            string csv = "";  
            //only the last table has data
            csv = ToCSV(dataSet.Tables[dataSet.Tables.Count - 1], "\t"); //Excel uses TabStop by default for csv  
            return csv;
        }
        private static string ToCSV(this DataTable table, string delimator)
        {
            var result = new System.Text.StringBuilder();
            for (int i = 0; i < table.Columns.Count; i++)
            {
                result.Append(table.Columns[i].ColumnName);
                result.Append(i == table.Columns.Count - 1 ? "\n" : delimator);  
            }
            foreach (DataRow row in table.Rows)
            {
                for (int i = 0; i < table.Columns.Count; i++)
                {
                    result.Append(row[i].ToString());
                    result.Append(i == table.Columns.Count - 1 ? "\n" : delimator);  
                }
            }
            return result.ToString().TrimEnd(new char { '\r', '\n' });  
        }
    }
}