在符合条件的行之后选择三行

We've got 7 guys travelling in Poland ( ;) ). The problem is to find up to three next cities they visited from the time they visited Warsaw. If one guy visits Warsaw twice, it is also counted as a starting point for the next journey. For example guy 1 have had not only a journey - Warsaw, Cracow, Warsaw, Gdansk, but also Warsaw, Gdansk.We've got 7 guys travelling in Poland ( ;) ). T