Chikyu Sentai Fiveman

In 1970, Doctor Hoshikawa was researching how to transform the planet Sedon into a green, lush world, testing it by attempting to grow flowers. On the day the first flower bloomed, the Zone Empire launched an assault on the planet, he and his wife were separated from their five children. Arthur G6 took the five children back to Earth and raised them. And then in 1990, the five are now teachers in the same school. (wikipedia)