Convert HTML select/optgroup to Flex

New to Flex, what is the nearest equivalent to the following HTML markup in Flex?

<select size="9">
    <optgroup label="Group 1">
     <option>Value 1</option>
     <option>Value 2</option>
    </optgroup>
    <optgroup label="Group 2">
     <option>Value 5</option>
     <option>Value 6</option>
    </optgroup>
    <optgroup label="Group 3">
     <option>Value 8</option>
     <option>Value 9</option>
    </optgroup>
</select>

From stackoverflow

• There is none that maps directly. You could try this -- a sample implementation (using Combobox) or to roll your own using either Combobox or RadioButtonGroup.

  Dave : That is swell thanks!