The Seven Ninja Swordsmen of the Mist (霧の忍刀七人衆, Kiri no Shinobigatana Nananin Shū) is an organization consisting of only the greatest blade-wielding shinobi of their generation that Kirigakure can produce. There can only be seven members at a time, hence the name. Four members are currently known, although the third, Raiga, only appeared in the anime.
They are like the Akatsuki. They have many members, but only 10 of the strongest are given the rings. The rest are just underlings.
Same issue here, The Seven Ninja Swordsmen of the Mist are the 7 strongest swordsmen in Kirigakure. In other words, there are other swordsmen in Kirigakure. What I am offering is "a swordsmen of Kirigakure" not "The Seven Ninja Swordsmen of the Mist".
Those who roleplay The Seven Ninja Swordsmen of the Mist will not be affected. Since they claim to be the strongest 7, and not just any Kirigakure swordsmen.
In my opinion, Suigetsu is a swordsmen of the Mist, not one of The Seven Ninja Swordsmen of the Mist. He was trained, but wasn't given a sword and a title like Zabuza & Kisame (the demon & the monster of the mist).