Cascaded list view , how to reach items in lvl1 from lv2

Question

I have a cascaded ListView and I want to reach objects in lvl1 from lvl2

<asp:ListView ID="LV1" runat="server">
    <ItemTemplate>
        <div class="col-12 p-2 border">
            <asp:TextBox ID="txtOID" class="hidden" runat="server" Text='<%#DataBinder.Eval(Container.DataItem,"OID")%>' />
            <asp:Button ID="BTNObiectiv" runat="server"
                Text='<%#Eval("Obiectiv")%>'
                OnClick="LV1_Click"
                UseSubmitBehavior="false"
                Style="font-size: 11px; background-color: lightgreen; width: 200px;" class="btn form-control form-control-sm"
                ClientIDMode="Static" />
            <div class="row no-gutters">
                <div id="DivS" runat="server" class="" clientidmode="Static">
                    <asp:ListView ID="LV2" runat="server" Visible="false">
                        <ItemTemplate>
                            <asp:TextBox ID="txtCID" class="hidden" runat="server" Text='<%#DataBinder.Eval(Container.DataItem,"CID")%>' />
                            <div class="col-12 p-2 border">
                                <asp:Button ID="BTNCladire" runat="server"
                                    Text='<%#Eval("Cladire")%>'
                                    OnClick="LV2_Click"
                                    UseSubmitBehavior="false"
                                    Style="font-size: 11px; background-color: lightsalmon; width: 180px;" class="btn form-control form-control-sm"
                                    ClientIDMode="Static" />
                            </div>

In code behind I handle the conection with:

protected void LV1_Click(object sender, EventArgs e)
{
    Button cmd = (Button)sender;
    ListViewItem ObiectivRow = (ListViewItem)cmd.NamingContainer;

    TextBox id = (TextBox)ObiectivRow.FindControl("txtOID");
    ListView LstCladire = (ListView)ObiectivRow.FindControl("LV2");

    LstCladire.DataSource = null;
    LstCladire.DataBind();

    int oid = Convert.ToInt32(id.Text);

    List<SqlParameter> prm = new List<SqlParameter>
    {
        new SqlParameter("@OID", oid)
    };

    LstCladire.DataSource = GetDataTableEvaris("SELECT DISTINCT CID,Cladire FROM tblCladire WHERE OID= @OID;", prm);
    LstCladire.DataBind();

    if (LstCladire.Visible)
    {
        LstCladire.Visible = false;
        return;
    }

    LstCladire.Visible = true;
    
    SqlParameter prmS = new SqlParameter("@OID", oid);
    hiddenObiectiv.Text = ExecuteScalar("SELECT DISTINCT Obiectiv FROM tblObiectiv WHERE OID= @OID;", prmS);
    hiddenObiectiv.Visible = true;

    hiddenCladire.Text = string.Empty;
    hiddenCota.Text = string.Empty;
    hiddenCamera.Text = string.Empty;
}

protected void LV2_Click(object sender, EventArgs e)
{
    Button cmd = (Button)sender;
    ListViewItem CladireRow = (ListViewItem)cmd.NamingContainer;

    TextBox id = (TextBox)CladireRow.FindControl("txtCID");
    ListView LstCota = (ListView)CladireRow.FindControl("LV3");

    LstCota.DataSource = null;
    LstCota.DataBind();

    int cid = Convert.ToInt32(id.Text);

    List<SqlParameter> prm = new List<SqlParameter>
    {
        new SqlParameter("@CID", cid)
    };

    //aici se incarca imaginea pentru cota

    LstCota.DataSource = GetDataTableEvaris("SELECT DISTINCT EID,Cota FROM tblCota WHERE CID = @cid;", prm);
    LstCota.DataBind();

    if (LstCota.Visible)
    {
        LstCota.Visible = false;
        return;
    }
    LstCota.Visible = true;

    SqlParameter prmS = new SqlParameter("@CID", cid);
    hiddenCladire.Text = ExecuteScalar("SELECT DISTINCT Cladire FROM tblCladire WHERE CID= @CID;", prmS);
    hiddenCladire.Visible = true;

    hiddenCota.Text = string.Empty;
    hiddenCamera.Text = string.Empty;

}

But I want to disable LstCladire which is in LVL1 from LVL2 procedure on a button click