My organization is intimately involved with Hisardut, not because the styles are somehow related, but because the head of my style is very good friends with Dennis Hanover, founder of Hisardut.
Hisardut is a style developed by Dennis, who spent his early years in South Africa, where he was constantly under persecution for being Jewish. Hisardut, which is the Hebrew word for "survival", is a style that focuses on strength. Most of the attacks are body shots, there's a lot of groundwork, and an emphasis on learning through experience (read: pain). Dennis is based in Herzliya, Israel.
KM and Hisardut are in no way related. Dennis deeply respects Imi Lichtenfeld and Haim Zut (head of KMF), as well as Krav Maga as a stlye. I had the honor of having Dennis at my instructors' course, and he is known to have said (more than once) that Krav Maga is the most efficient system that he knows.