Manage two radioButton

[Colince]

I have 2 radiobuttons on my grid that are mutually exclussive and i also have on checkbox. This 2 radiobuttons are enabled/disabled when i click on the checkbox using javascript function. I have in the code behind the method manageSelected which are call while clicking on the button save. Initially the 2 radiobuttons are enabled.  Without the javascript function all thing work fine(i can check one of the radiobutton and save his value). My issue is that when i apply the javascript it work only in one way(I can change my object property value from value of radiobutton1 to the one of radiobutton2 and not mutual).
 

My file.aspx

<tr>
                    <td>
                        <asp:CheckBox ID="rbDiscountGoodCalcTypeSet" runat="server" BackColor="red" onchange="onChangeDiscountGoodCalcType()"/>
                        <asp:Label ID="lbDiscountGoodCalcType" runat="server" Text="<%$ Resources: Common, DiscountGoodCalcType %>"></asp:Label>
                    </td>
                    <td colspan="3">
                        <asp:RadioButton ID="rbDiscountGoodCalcType1" GroupName="DiscountGoodCalcType" runat="server"
                            Text="<%$ Resources: Common, ByQuantity %>" Checked='<%# Eval("DiscountGoodCalcType").ToString() == "0" %>' Enabled="false"/>
                        <asp:RadioButton ID="rbDiscountGoodCalcType2" GroupName="DiscountGoodCalcType" runat="server"
                            Text="<%$ Resources: Common, ByValue %>" Checked='<%# Eval("DiscountGoodCalcType").ToString() == "1" %>' Enabled="false"/>
                    </td>
                </tr>

My javascript function

function onChangeDiscountGoodCalcType() {
            var sourceName = window.event.srcElement.id;
            var targetName1 = sourceName.substring(0, (sourceName.length - 3)) + "1";
            var targetName2 = sourceName.substring(0, (sourceName.length - 3)) + "2";

            var cmdObj = $("#" + sourceName)[0];
            var targetObj1 = $("#" + targetName1)[0];
            var targetObj2 = $("#" + targetName2)[0];

            targetObj1.disabled = !cmdObj.checked;
            targetObj2.disabled = !cmdObj.checked;
        }

My savebutton call this method for the control

private void Manage4Line()
        {
            if (rbDiscountGoodCalcTypeSet.Checked)
                DiscountGoodCalcType = (rbDiscountGoodCalcType1.Checked) ? 0 : 1;
        }

Thanks