A group of people are in front of a building with flags.
Some people are in front of a building.
"Some" is a rephrasing of "a group of."
exists p1 x1 x2.(exists x3 x4 x5.(in(x1,x3) & of(x3,x4) & with(x4,x5) & n_flag(x5) & n_building(x4) & n_front(x3)) & of(x1,x2) & n_people(x2) & n_group(x1))
exists p1 x1.(exists x2 x3.(in(x1,x2) & of(x2,x3) & n_building(x3) & n_front(x2)) & n_people(x1))