formula for staff rotas
 

On a staff rota, I need three formula to calculate the number of opening,
evening and closing staff on a daily basis. Depending on the day staff may
begin at 11:00 and finish at 18:00 or continue on until 23:00, a second set
of staff come in between 17:00 and 18:00, I need a way to show how many staff
are in at any one time, broken into categories, opening ( between 11:00 and
18:00) Evening (17:00 to 22:00) and Closing (how many people are rota'd on to
finish - 23:00)

This information would need to be organised into a simple 3 row, 7 column
table

Hope someone can help?