we have to groups of subjects, A and B, and N measures.

If we test all N measures for differences between A and B we obtain N p values (let's call this set P0).

The, we propose a way to extract subgroups from one of the two groups say A1, A2 (whose intersection is null and whose union is A).

Now, we have N p values for the test A1 vs B, and N p values for the test A2 vs B (let's call these sets P1 and P2 respectively).

What is the correct way to compare P0, P1, and P2?

thanks