Have Two Levels Of Subtotals In Spreadsheet?

I have a report of employees' hours reported for the week, which I process payroll from.

I have sorted the spreadsheet first by employee number, and then by date. I have subtotaled each day's hours (with a formula rounding each day's hours to the nearest quarter hour).

I now need to add a subtotal of weekly hours, per employee number, and I cannot figure out how to do this.

Here is an example of what I want to do. I have highlighted the second subtotal I want to add to the spreadsheet, but have been doing the =sum(xxx) formula for each employee because I can't figure out how to subtotal again.

David L 9/30/2013 0005 360 6:00 A.M. 12:00 P.M.
David L 9/30/2013 0005 112 12:30 P.M. 2:22 P.M.
David L 9/30/2013 0005 115 2:22 P.M. 4:17 P.M.
David L 9/30/2013 0005 13 4:17 P.M. 4:30 P.M.

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