I hope Kurumi isn't planning to first become Sawako's good friend, then telling her she loves Kazehaya and asking Sawako to support her, thus reducing Sawako's own efforts as she couldn't possibly backstab Kurumi, whom she should be supporting.

But in the end no matter what Kurumi does, it won't change the fact Kazehaya already loves Sawako. So, Kurumi's greatest achievement wouldn't ever be more than to keep those two apart.