A family is hiking across a rocky landscape.
a group of individuals walk about on some rocky terrain
A family is a group of individuals.  Rocky terrain is the same as a rocky landscape.
exists e1 s1 x1 x2.(across(e1,x2) & n_landscape(x2) & a_rocky(s1) & Theme(s1,x2) & Actor(e1,x1) & v_hike(e1) & n_family(x1))
exists e1 s1 s2 x1 x2 x3.(on(e1,x3) & n_terrain(x3) & a_rocky(s2) & Theme(s2,x3) & a_about(s1) & Manner(e1,s1) & Actor(e1,x1) & v_walk(e1) & of(x1,x2) & n_individual(x2) & n_group(x1))