[Solved] Cascading multi-select comboboxes

[Baal]

I have two comboboxes, one dependent on the other. There's a checkbox beside each item in each combobox so users can make multiple selection on each. This is how both my comboboxes are coded.

            <input id="hdnProduct" runat="server" type="hidden" />
            <telerik:RadComboBox ID="rcbProduct" runat="server" EmptyMessage="All" HighlightTemplatedItems="true" AllowCustomText="true"
                OnClientDropDownOpening="rcb_ClientDropDownOpening" OnClientDropDownClosing="rcb_ClientDropDownClosing"
                OnClientSelectedIndexChanging="rcb_ClientSelectedIndexChanging" OnClientBlur="rcb_ClientBlur">
                <ItemTemplate>
                    <asp:CheckBox ID="chk" runat="server" onclick="rcbProduct_CheckBoxClicked();" />
                </ItemTemplate>
            </telerik:RadComboBox>

Based on every checkbox clicked, it appends the selected text in the text area on the combobox and value in the hidden input field.

After I finish making my selection here, I need to populate another combobox (which is coded in the same style) to be populated dynamically. Right now the problem I am having is how can I do it? Do I use the ClientItemRequested and ItemsRequested methods in the second combobox to populate it? Will doing so have any problem with creating the checkboxes dynamically? If so then do I need to do a full postback after the selection is complete in the first combobox (I don't want to do a full postback if possible)? Is there a better solution to this?

Thanks.