How to Store "Nested groups of checkboxes" ?

Question

Hi I have a form (form1) which should gather information from user and save them into DB. In form1, I have 4 different groups:

Group1: Operational Costs(Material, Salary, Maintenance)
Group2: Selling Costs(Advertisement, Transport, Operational Costs)
Group3: Financial Costs (Benefit, Penalty)

Every option like Material, Salary, Maintenance, Advertisement,...Penalty should have a checkbox control in order to get what the user's option.

As you see above, Group2 contains 3 branches and the last one of them is Group1.

Now, What is the best design for a table for saving data into DB form this form?

I use SQL Server 2005 and Vb6.0. THANK YOU