brethren

veljet, uskonveljet puhekieltä (monikko) brother|lang=en
puhekieltä the body of members, especially of a fraternal, religious or military order
Of or akin to; related; like
2009, Seth Shostak, Confessions of an Alien Hunter:

The principle still sounds good, but our astronomical knowledge is limited, and we haven't yet discovered any such brethren solar systems.