The Zodiac Cartel was founded by Cornelius van Lunt (Taurus), handpicking the eleven other members; van Lunt concealed his own identity, while he was the only one who knew the identities of the others.
The Zodiac Cartel was formed by Cornelius van Lunt (Taurus) who chose the other eleven members himself, and he remained unknown to everyone except for him knowing their true identities.