message mapping

<xyz attr="R">  --->n number of times

<a>a1</a>
<b>b1</b>
<c>c1</c>

</xyz >

<xyz attr="L">  -------------n number of times

<a>a2</a>       ---->only 1
<b>b2</b>      ---->ony 1
<c>c2</c>       ---->only 1
</xyz >

<xyz attr="L">

<a>a3</a>
<b>b3</b>
<c>c3</c>

</xyz >




I need the output :





<xyz attr="R">

<a>a1</a>
<b>b1</b>
<c>c1</c>
</xyz >

<xyz attr="L">

<a>a2</a>
<b>b2</b>
<c>c2</c>
<a>a3</a>
<b>b3</b>
<c>c3</c>
</xyz >


how to do this