Students walking down the road.
A group of students walk to school.
They could be walking anywhere, not necessarily to school. And it could be just two, not necessarily a group.
exists e1 x1 x2 x3.(n_road(x3) & a_topic(x1) & down(e1,x3) & Actor(e1,x2) & v_walk(e1) & (x1 = x2) & n_student(x1))
exists e1 x1 x2 x3.(to(e1,x3) & n_school(x3) & Actor(e1,x1) & v_walk(e1) & of(x1,x2) & n_student(x2) & n_group(x1))