In a traditional Japanese dojo, three martial artists -- Hiroko, Takeshi, and Emiko -- train under different senseis. Hiroko's sensei is Master Kazuo, while Takeshi trains under Master Akio. Emiko, who specializes in the same martial art as Hiroko, also trains under Master Kazuo. Takeshi and Emiko recently decided to demonstrate a paired kata routine for a local cultural festival. Considering these relationships, determine who shares a sensei with whom and describe Hiroko's involvement with the paired kata routine. Also, specify what responsibilities Master Kazuo has with respect to his students. Provide a brief response.
Hiroko and Emiko share the same sensei, that is Master Kazuo, indicating that both martial artists receive their training in the same discipline from the same instructor. Takeshi, on the other hand, trains under a different instructor, Master Akio, therefore does not share a sensei with Hiroko or Emiko.

As for the paired kata routine, Hiroko is not directly involved since it is Takeshi and Emiko who have decided to perform together at the cultural festival. Hiroko's training and activities remain separate from this particular demonstration unless stated otherwise.

Master Kazuo is responsible for training both Hiroko and Emiko in their chosen martial art. He would provide guidance, instruction, and mentorship to them both. However, in the context of the cultural festival demonstration, Master Kazuo may only have direct involvement in training Emiko for the paired kata routine with Takeshi if the routine is part of his discipline. If not, his involvement with the routine would be indirect or non-existent.