Time - Schedule Format

[TheDanielStern]

I currently have a csv file that auto populates shifts. Since I have graveyard employees I often have overlap. I need a formula or macro that will adjust the start or end times based on a logical test.
Example - if an employee starts on September 2nd and their shift extends into the 3rd, my schedule for the 3rd shows them as 21:00-05:30. Since my day begins at 03:30 I need to show their new day schedule as 03:30 - 05:30. Conversely, if an employee is scheduled for the 21:00-05:30 shift on the 3rd, I need it to show 21:00-03:59, my current sheet only counts by the quarter hour.

Any help would be great.