I am designing a schedule for about 20 employees which includes a first and
second shift. The hours are not identical. For example, some work 6am-4pm,
9am-7pm, 9am-5pm, 2pm-12midnight, 4pm-12midnight, etc.

I am wondering if it is possible to have an automatic calculation for each
day how many staff are scheduled for first shift, and how many are scheduled
for second shift. Of course, I would have to define each shift and whether
it classifies as first or second. How do I do this?

Thank you so much for your help!