I have a list of sub-totalled parts similar to this:

Part x Description 1 Used on Car 1
Part x Description 2 Used on Car 2
Part x Description 3 Used on Car 3
Part x Total 6

Part y Description 2 Used on Car 2
Part y Description 3 Used on Car 3
Part y Total 5

Part z Description 5 Used on Car 1
Part z Total 5

There are three different parts x, y and z which are used in differing
quantities on different models of cars.

I want to know:
a) how many parts are used only on car 1, only on car 2, etc.
b) how many parts are used on car 1 and car 2
c) how many parts are used on car 1, car 2 and car 3
etc.

for all of the various combinations.

Any ideas?

Garth