How to calculate subtotal and show heading in sql server reporting 2008 R2

I have data like picture below

I want to display my data like this

So I want to know how can i show group 01 02 03 and then calculate their respective to开发者_运维知识库tals in sql server reporting 2008 R2.

Is there any built-in technique to do this ?

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Create a group with the expression below

=Mid(Fields!Code.Value,1,2)

Mid is similar to sql Substring function