How to achieve this ?
Input
-------

<TestRequest >
	<Category>Hem</Category>
	<Action>NW</Action>
	<Results>
		<Observation>
			<SpecimenType>CSF</SpecimenType>
			<ResultCategory>CELLMARK</ResultCategory>
		</Observation>
		<Observation>
			<SpecimenType>MSF</SpecimenType>
			<ResultCategory>Tissue</ResultCategory>
		</Observation>
		<Observation>
			<SpecimenType>CSF</SpecimenType>
			<ResultCategory>Skin</ResultCategory>
		</Observation>
		<Observation>
			<SpecimenType>MSF</SpecimenType>
			<ResultCategory>Hair</ResultCategory>
		</Observation>
	</Results>
</TestRequest>


Expected Output - 2 xmls grouped by Specimen Type.
--------------------------------------------------


<TestRequest >
	<Category>Hem</Category>
	<Action>NW</Action>
	<Results>
		<Observation>
			<SpecimenType>CSF</SpecimenType>
			<ResultCategory>CELLMARK</ResultCategory>
		</Observation>
		<Observation>
			<SpecimenType>CSF</SpecimenType>
			<ResultCategory>Skin</ResultCategory>
		</Observation>
	</Results>
</TestRequest>


<TestRequest >
	<Category>Hem</Category>
	<Action>NW</Action>
	<Results>
		<Observation>
			<SpecimenType>MSF</SpecimenType>
			<ResultCategory>Tissue</ResultCategory>
		</Observation>
		<Observation>
			<SpecimenType>MSF</SpecimenType>
			<ResultCategory>Hair</ResultCategory>
		</Observation>
	</Results>
</TestRequest>

Regards
Gururaja