Over time formula needed

Hi,
I have been trying to figure out a formula for over time. The way our over time works is this:

If you work 2 hours or less you get paid 3 hours of straight time over time (STO)

If you work 2 hours or more you get paid the first 2 hours at 1 1/2 (1.5X) times (THO) and the rest at 2X (DTO).

For example,
I work 1.5 hours = 3 hours at STO
I work 4 hours = 2 hours at THO and 2 hours at DTO.

I would like to develop a Time Sheet where I can enter my total time worked and the sheet will calulate what hours are put into the 3 columns above.

Over Time Explanation Hours Wrkd STO THO DTO
Completing contract 1 1.5 3
Completing contract 2 4.0 2 2
Completing contract 3 7.0 2 5

Totals 3 4 7



Any help would be appreciated.

Russ