A group of participants are having a meeting.
People are in a meeting.
" group of participants " can be deduced to mean " people " and " meeting " is the direct object of both verbs.
exists e1 x1 x2 x3.(Theme(e1,x3) & Actor(e1,x1) & v_have(e1) & n_meeting(x3) & of(x1,x2) & n_participant(x2) & n_group(x1))
exists p1 x1.(exists x2.(in(x1,x2) & n_meeting(x2)) & n_people(x1))