VS 2008 ListView Grouping Sort

Good day vbforums. is there any one can help to solve my simple problem. In my Listview i add a group and my problem is
how to sort a group by ascending type. if i run th project the grouping display like this..

Group Display:

Pent House
----- Name1
----- Name2
----- Name3
Admin Office
----- Name1
----- Name2
General Service Office
----- Name1
----- Name2
Processing Office
----- Name1

I want is auto sort from A to Z

Admin Office
----- Name1
----- Name2
General Service Office
----- Name1
----- Name2
Pent House
----- Name1
----- Name2
----- Name3
Processing Office
----- Name1

So please help me to solve this problem. Thanks and advance