Dynamic DataTable Adding group header

Hello,

I am trying to render a list dynamically but want to create a group header when a certain columns is changed:
Currently I have the floowing which works to show the list:

rows: productList.map((onechild) {
                    return DataRow(
                        cells: [
                          DataCell(
                              Container(
                                  width: 120, child: Text(onechild.group)),
                              showEditIcon: false,
                              placeholder: false),
                          DataCell(
                              Container(width: 120, child: Text(onechild.name)),
                              showEditIcon: false,

                              placeholder: false),
                          DataCell(
                              Container(width: 120, child: Text(onechild.uom)),
                              showEditIcon: false,
                              placeholder: false),
                          DataCell(Checkbox(
                              value: onechild.active,
                              onChanged: (

                                bool value,
                              ) {
                                switchActive(onechild.id);
                              })),
                          DataCell(IconButton(
                            icon: Icon(Icons.delete),
                            onPressed: () {
                              showAlertDialog(context, onechild);

                            },
                          ))
                        ]);
                  }).toList()),

I am quite fresh to Flutter and Dart. How is it possible to return two Rows for one item in my list when a group key is chaninging

Regards,
Carsten.