Urgent: Grouping attributes together

<school>
 <student class="A">L</student>
 <student class="B">M</student>
 <student class="A">O</student>
 <student class="C">P</student>
 <student class="B">Q</student>
 <student class="C">R</student>
 <student class="A">S</student>
</school>

 <Section class="A">
    <student >L</student>
    <student >O</student>
    <student >S</student>
 </Section>

<Section class="B">
    <student >M</student>
    <student >Q</student>
</Section>

<Section class="C">
    <student >P</student>
    <student >R</student>
</Section>

Thanks in advance
Bhargav