Grobman established the Leviathan Group in 1975 in collaboration with Avraham Ofek and Samuel Ackerman. The style of the group represented a blend of contemporary art, Jewish themes, symbolism, and metaphysics. In the manifesto entitled "The Leviathan Declaration, " publicized in 1976, Grobman set forth the group's goals: "Our joint appearance is an incipient attempt to create an inclusive national style that befits the spirit of the building of the New Israel […], our political basis [is] Zionism. Our spiritual basis – Jewish mysticism. Three foundations define our artistic stance: 1. Primitivism 2. Symbol 3. Letter."