Total time between intervals

Hi,

I want to calculate how much services are produced during chosen intervals. I have only one service and start and end times (hours:minutes:seconds). There is multiple workers producing service during day. I want check how much service hours are produced between hours. So intervals are then for example 8:00-9:00, 9:00-10:00 and so on. I dont know how to do it or should I use functions or pivot. I put example sheet to attachments.

-J