Expand List Based on Duration

I've got a unique data set that needs to get expanded based on a duration listed in the data set. My data has Year, Month, Day, Start Hour, & Duration Days all listed in separate columns. Given the duration days I need to add all missing hours to my data set. However, duration days is not obvious. The first day is assumed to be from the start Hour to hour 24. If the start hour where 23, then I would need to add data for hour 24 only and that would be 1 day. Here is an example of what i'm after.... looking at row 2 the data says Jan 27, 2010 hour 12 with a duration of 2 days. So I need to add hours 13-24 for the 27th (that's 1 day), and hours 1-24 for the 28th (that's the 2nd day) to my data set. Is it possible to automate that?? Ideally a macro would create a new list with all original hours plus all additional hours.