Unlike Children Palace 子女宫 which is no longer accurate in predicting
the number of children one may have (due to the many many
contraceptive methods), Siblings Palace 兄弟宫 is able to indicate
how many siblings one has (depending on what are the stars in the palace).
兄弟宫 「Xiōng Dì Gōng 」 is indicative of one's relationship with his
siblings; whether there is siblings rivalry or unison. Besides blood
siblings, it also covers close friends and buddies - those who are so
so close that one probably sees them more than his/her own siblings.
However, these close friends will have to be those of the same generation.
For businessmen, 兄弟宫 represents business partners.