A group of people attending an event.
A group of people are at an event.
Attending is another way of saying are at an event.
exists e1 x1 x2 x3 x4.(a_topic(x1) & of(x1,x2) & Theme(e1,x4) & Actor(e1,x3) & v_attend(e1) & n_event(x4) & (x2 = x3) & n_people(x2) & n_group(x1))
exists p1 x1 x2.(exists x3.(at(x1,x3) & n_event(x3)) & of(x1,x2) & n_people(x2) & n_group(x1))