Calculating hours using pivot table

Hi,

I'm making a personell planning sheet and I want to calculate the sum of hours teachers give lessons. I have 2 tables and my data is formatted like this (simplified)

Now I want to create an overview of how many hours each teacher is teaching using a pivot table.

This is easy when there is just one Teachter collumn but I need to calculate the sum using both teacher collumns...

 I need to overview to be something like this:

• Paul -> Lesson 1 + Lesson 3 = 4 hours
• Pete -> Lesson 2 + lessen 3 = 5 hours

Then the next step is to use a metric or KPI to calculate if each teacher is exceeding their max working hours...

Can anybody hlelp me with these problems?

Thanks!