A group of people do tricks on motorbikes.
People do tricks for a crowd.
Just because people do tricks does not mean they do it for a crowd.
exists e1 x1 x2 x3 x4.(on(e1,x4) & n_motorbike(x4) & Theme(e1,x3) & Actor(e1,x1) & v_do(e1) & n_trick(x3) & of(x1,x2) & n_people(x2) & n_group(x1))
exists e1 x1 x2 x3.(for(e1,x3) & n_crowd(x3) & Theme(e1,x2) & Actor(e1,x1) & v_do(e1) & n_trick(x2) & n_people(x1))