Dragonwings is a historical novel for kids. It tells the story of a Chinese family in San Francisco.
This story was rewarded for its quality to reproduce historical events and allow new generations to understand their importance; it was then adapted to film because of the same reasons. However because of the length of the film several parts were summerized.
The scene in the novel that reads "...Besides that there was the Lee family building, which would help everyone who was named Lee." helps the audience understand the way chinease people would help each other in their new context, and form new relations, even though not all lees might have been family, it served them as a way to work together.
Even though it is mentioned in the film, it is not included as the important piece of context that it is in the book.