i think i got your idea, but i dont really understand your code :P
you create too many classes (and structs; why do you use both, if its basically the same thing?), so its hard to keep track of whats going on in this soup of variables with similar names.
why don't you create a single class for the screens, each one containing a vector of circles? like this:
class Screen{
std::vector<sf::CircleShape> circles;
};
then, in your code, you can just create an array of Screens, and each one will have its own number of circles:
Screen screens[4];
let me know if you have any trouble putting this in practice. or if you really need to use the code like you posted, you need to explain it a bit more.