Create and filter subgroups?

Hi,
Im using Datareport in vb6.0 and want to know how create subgroups and filter them. Im working with tables Item(Itemno,Name,Category), PInvoice(InvoiceNo,Date,Total) and PInvoice2(InvoiceNo,ItemNo,Price,Quantity)
I want a report like:

Quote:

---

Category(user specified)
----------------------------
Date (user specified)
-------------------------
InvoiceNo
ItemNo
Price
Quantity
----------
InvoiceNo
ItemNo
Price
Quantity
----------
(All invoices on that particular date)
----------
Total : (Total of all invoices on that date)
----------------------------
(Date sub group to be repeated for a range of dates seleted by user)
----------------------------
Grand total : (Total of all invoices in selected category)

---

So far Ive been able to filter by date or category alone but cannot combine both in one single report. Can someone help me out with this?