calculating a time range into predefined time slots

I have a two columns one with a start time and the other with an end time. These times can be any amount of time during the day and in 24 hour time format for example the start could be 03:43:00 and the end could be 6:13:00. I then have 6 other columns that break the day up into 4 hour time slots for example the first is 0:01-4:00 second 4:01-8:00 and so on. What my objective is to calculate the sum of the hours using only the start and end times and then separate the totals into each time slot. So using the above example of the start 03:43:00 we will say it is A1 and the end 6:13:00 in B1 then 00:17:00 would be in the 0:01-4:00 time slot and 02:13:00 would be in the 4:01-8:00 time slot.

I have a good knowledge of web programming and databases but I just don't know excel forumulas very well. If I can't get this I'm just going to make a database and use a web UI to do my queries but here is an example of what I started doing for the first time slot but I know its way off the mark
=SUM((B1<=TIME(4,0,0))-(A1>=TIME(0,1,0)))