Queries :: Calculating Working Hours Of Employee

We are trying to find a way to have a query figure out when the hours of an employee reach 40 hours (Overtime) and figure the hours correctly. The Data Entry table contains the basic fields:

[Workdate].....The date the work was done
[WEDate].......The Week Ending Date. Always on Sunday, and calculated like this "[WorkDate]-Weekday([WorkDate]-1)+7"
[Employee].....Employee Name
[Qty].............# of hours worked that day
[RegHours].....Blank, to be updated by query
[OTHours]......Blank, to be updated by query

The problem we are running into is getting it to update the daily running totals (using the [WEDate] & [employee] as the "Group Bys"). We'd like use an update query to fill in the to blank fields with the correct calculations.

Example - Working 6 day week, at 9 Hours per day in the [Qty] field

Day.............[RegHours]......[OTHours]
Monday..............9..................0
Tuesday............18..................0
Wednesday........27..................0
Thursday...........36..................0
Friday...............40..................5
Saturday...........40.................14
Sunday.............40.................23

We have tried several things to get it to compute this field and haven't had much luck.