Web Forms :: Counting The Checkboxs And Checkboxlixt Validation?

I have the following simple logic on my buttionclick. Along with this, I need to implement my checkboxlist validation and need to find if more than one boxes are checked.

I attemtpted diffferent things by goggling, nothing worked. I would appriciate your help.

protected void Button1_Click(object sender, EventArgs e)
{
foreach (ListItem item in CheckBoxList1.Items)
{
if (item.Selected)
{
//item.Text and item.Value will give you other properties...
if (item.Text == "CSG")
{
Response.Redirect("page2.aspx");
}
if (item.Text == "GGSN")
{
Response.Redirect("page3.aspx");
}
}
}
}