   <optgroup label="Group 3">
          <option value="7">Option 7</option>
          <option value="8">Option 8</option>
          <option value="9">Option 9</option>
          <option value="10">Option 10</option>
        </optgroup>
      </select>
    </div>
  </div>

  <div class="mb-3 row">
    <label class="col-sm-2">
      Group Select2
    </label>

    <div class="col-sm-10">
      <select multiple="multiple">
        <optgroup label="Group 1">
          <option value="1">Option 1</option>
       