Emulate an HTML select optgroup with RichFaces 3.3 (seam is optional, just use <f:selectItems/> and a converter)

page.xhtml

<h:selectOneMenu value="#{myObject.value}">
	<s:selectItems value="#{app.globalList}" var="_o" label="#{_o.label}" noSelectionLabel="-" />
	<f:selectItem itemValue="-1" itemLabel="-------" itemDisabled="true" />
	<s:selectItems value="#{app.globalListComplement}" var="_o" label="#{_o.label}" />
	<s:convertEntity />
</h:selectOneMenu>