/** @OnlyCurrentDoc */

function getGroup(sheet, rowIndex) {
  var groupDepth = sheet.getRowGroupDepth(rowIndex);
  if (groupDepth) return sheet.getRowGroup(rowIndex, groupDepth)
  else return null
}

function remove_all_groups() {
  var spreadsheet = SpreadsheetApp.getActive();
  var sheet = spreadsheet.getActiveSheet();
  var endRow = sheet.getLastRow();
  
  for (var row = 1; row <= endRow; row++) { 
    var group = getGroup(sheet, row);
    while (group) {
      group.remove();
      group = getGroup(sheet, row);
    }
  }
};

function group_rows() {
  
  remove_all_groups();
  
  var spreadsheet = SpreadsheetApp.getActive();
  var sheet = spreadsheet.getActiveSheet();
  var endRow = sheet.getLastRow();
  var endCol = sheet.getLastColumn();

  var row = 10;
  var new_group_row = 10;
  while (row <= endRow) {
    var new_group = ! sheet.getRange(row, 1).isBlank()
    

    if (new_group) {
      if (row - new_group_row > 2) {
        
//        sheet.getRange(row-2,2).setValue(new_group_row);

        sheet.getRange(new_group_row+1, 1, row - new_group_row - 1).shiftRowGroupDepth(1);
        
        getGroup(sheet,new_group_row+1).collapse();
      }
      new_group_row = row 
    }  

    row++;
  }
};