Question with double role

Hi,
I’ve the following role/product configuration :

– Product “A” must be visible for users role “a”, but invisible for users role “b”
– Product “B” must be visible for users role “b”, but invisible for users role “a”

At this time, I made this setting in the “Visible” and “Invisible” boxes for both products.

BUT I also have some users who have the double role (let’s say primary role “a” and secondary role “b”). These ones must see both product “A” and “B”.

… and it doesn’t work : users a/b don’t see anything!

How should I do?

Thanks!