How to Group the Record in Biztalk map

I have a Schema in which i need to group the Record based on customerID.

<CustomerID>

<Item></Item>

%ufeff%ufeff</customerID>

The Output has to be ordered in the following fashion based on CustomerID

Output Schema

%ufeff<CustomerID>

<Items>

<Item>

</Item>

</Items>

</CustomerID>

How to Sort the Same in Ascending Order.

I want to use the Functoids.(Condition not to use Scripting Functoid and Custom XSLT)

How to accomplish this in Biztalk MAP GUI.

Thanks in Anticipation.