See the following example

<ext:GridPanel
ID="grdFaults"
runat="server"
Collapsible="true"
MinWidth="1040"

RowLines="true" Height="250" Resizable="false"
Frame="true"
Scroll="Vertical"
Header="false" Sortable Columns="false" EnableColumnHide="false" EnableColumnResize="true"
EnableColumnMove="false" Border="false" ForceFit="true" ClientIDMode="Static" >

<Store>
<ext:Store ID="strFaults" runat="server" GroupField="LegInfo">
<Model>
<ext:Model runat="server">
<Fields>
<ext:ModelField Name="LegInfo" />

<ext:ModelField Name="Occured" />
<ext:ModelField Name="Source" />
<ext:ModelField Name="Destination" />

</Fields>
</ext:Model>
</Model>

</ext:Store>
</Store>
<ext:Grouping
runat="server"
HideGroupedHeader="true"
GroupHeaderTplString='LEG INFO : {name} ({[values.rows.length]} {[values.rows.length
> 1 ? "Faults" : "Fault"]})' />
</ext:GridPanel>


output is generated as

LegInfo1
---------------------------------

date suorce destination

1-2-2017 abv xyz
2-2-2017 nnmn lmn
5-2-2017 hhb jjj
12-2-2017 nn mmm


Leginfo2
--------------------------------

date suorce destination
19-3-2017 abv xyz
20-3-2017 nnmn lmn
21-3-2017 hhb jjj
22-3-2017 nn mmm




Leginfo3
-------------------------------------
date suorce destination

14-2-2017 abv xyz
15-2-2017 nnmn lmn
16-2-2017 hhb jjj
17-2-2017 nn mmm

Here the Leginfo field is grouping filed

here my requirement is i need to group the Leginfofield and then i need to sort the leginfo which contains latest date comes firts

like expected output

Leginfo2
--------------------------------

date suorce destination
19-3-2017 abv xyz
20-3-2017 nnmn lmn
21-3-2017 hhb jjj
22-3-2017 nn mmm


Leginfo3
-------------------------------------
date suorce destination

14-2-2017 abv xyz
15-2-2017 nnmn lmn
16-2-2017 hhb jjj
17-2-2017 nn mmm

LegInfo1
---------------------------------

date suorce destination

1-2-2017 abv xyz
2-2-2017 nnmn lmn
5-2-2017 hhb jjj
12-2-2017 nn mmm