I want to have multiple dropdowns within a form custom control.

The following will render one dropdownlist. But I want to add another 4 dropdowns in addition to the one below.
The property name 'Items' is obtained from SelectionElementBlockBase and can only be used once to render one dropdown.

How can I create another dropdown using the approach below. SelectionElementBlockBase seems to allow one dropdown only

Public class selectlistsblock : SelectionElementBlockBase
{
[Ignore]
public override IEnumerable Items
{
get
{
var lst = new List();
var cats = GetCategories("department");
foreach (var cat in cats)
{
yield return new OptionItem { Caption = cat.LocalizedDescription, Value = cat.LocalizedDescription, Checked = false };
}
}

}
}