Mapping from two sources

I need to have two sources:

input1 and input2. 

input1:
<?xml version="1.0" encoding="ISO-8859-1"?>
<Order>
	<OrderLine>
			<OLN>1</OLN>
			<Fname>aa</Fname>
	</OrderLine>
	<OrderLine>
			<OLN>2</OLN>
			<Fname>bb</Fname>
	</OrderLine>	
</Order>


input2:
<?xml version="1.0" encoding="ISO-8859-1"?>
<POOrder>
	<POOrderLine>
			<OLN>1</OLN>
			<ID>123</ID>
			<LName>aa</LName>
	</POOrderLine>
	<POOrderLine>
			<OLN>2</OLN>
			<ID>324</ID>
			<LName>bb</LName>
	</POOrderLine>	
</POOrder>

I need the output from both sources combined. Please note that first two elements are coming from input1 and thrid element is from input2. What is the 
optimal way of doing this?

<?xml version="1.0" encoding="ISO-8859-1"?>
<OrderResponse>
	<Oline>
		<OLN>1</OLN>
		<Fname>aa</Fname>
		<ID>123</ID>
	</Oline>
	<Oline>
		<OLN>2</OLN>
		<Fname>bb</Fname>
		<ID>324</ID>
	</Oline>
</OrderResponse>