Foo XML

 <XMLObj>
    <ObjFoo id="fooObj.id" someStr="fooObj.someStr">
        <!-- Split the fooObj into groups based on the groupId, each group will have one ObjBars tag-->
        <ObjBars groupId="fooObj.subBar.groupId[0]">
            <!-- All ObjBar elements in this group have the same groupId -->
            <ObjBar id="fooObj.subBar.id[0]" />
            <ObjBar id="fooObj.subBar.id[1]" />
        </ObjBars>
        <ObjBars groupId="fooObj.subBar.groupId[1]">
            <!-- All ObjBar elements in this group have the same groupId -->
            <ObjBar id="fooObj.subBar.id[0]" />
            <ObjBar id="fooObj.subBar.id[1]" />
        </ObjBars>
    </ObjFoo>
</XMLObj>