Date grouping formula Crystal

Hi,

Our production cycle time is from 06:00 AM till 06:00 AM. When in a report i want to see the production figures group by date, it is doing the normal grouping that is 00:00 till 23:59 and then it changes the date. There is an option to put my own formula to group date.

For example, the below result should be in a single line. This is production of 02-June. (The cycle 06:00 AM 02 June till 06:00 AM 3 June is considered as production of 2 June only).

Can anyone please help me what would be the formula for starting the day at 06:00 AM and ending at 05:59 AM. (So the date change would be at 06:00 AM) not at 12 midnight.