gistfile1.js

// If not installed from the Apps Script Library to start form processing select Run > onInstall twice (once to authnticate), the second time to add the trigger
function doOnFormSumbit(e) {
  var doc = SpreadsheetApp.getActiveSpreadsheet(); 
  var sheetName = e.values[1]; // assuming field to split data by is first form element
  // see if new sheet
  var sheetToWrite = doc.getSheetByName(sheetName) || null;
  // if new sheet insert column headers
  if (sheetToWrite == null){
    var sheets = doc.getSheets();
    var sheetToWrite = doc.insertSheet(sheetName);
    var sheet = sheets[0]; // assuming first sheet has the column headers we need
    var colHeader = sheet.getRange(1, 1, 1, sheet.getLastColumn()).getValues();
    sheetToWrite.getRange(1, 1, 1, sheet.getLastColumn()).setValues(colHeader);
  }
  // copy form data submitted
  var insertRow = sheetToWrite.getLastRow()+1;
  sheetToWrite.getRange(insertRow, 1, 1, e.values.length).setValues([e.values]);
}

function onInstall(){
  if (ScriptApp.getScriptTriggers().length === 0) {
    ScriptApp.newTrigger("doOnFormSumbit")
        .forSpreadsheet(SpreadsheetApp.getActiveSpreadsheet())
        .onFormSubmit()
        .create();
  }
}