<table id="tbl1" runat="server">....</table>
<table id="tbl2" runat="server">....</table>
<table id="tbl3" runat="server">....</table>
<table id="tbl4" runat="server">....</table>

//code behind
protected HtmlTable tbl1;
protected HtmlTable tbl2;
protected HtmlTable tbl3;
protected HtmlTable tbl4;

protected override void OnPreRender(EventArgs e)
{
    tbl1.Visible = false;
    tbl2.Visible = false;
    tbl3.Visible = false;
    tbl4.Visible = false;

    switch (razdel)
    {
        case "1":
            tbl1.Visible = true;
            break;
        case "2":
            tbl2.Visible = true;
            break;
        case "3":
            tbl3.Visible = true;
            break;
        case "4":
            tbl4.Visible = true;
            break;
    }
}