Some people playing paintball.
A group of co-workers participated in paintball.
"Group of co-workers participated" is rephrasing of "some people playing"
exists e1 x1 x2 x3.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_play(e1) & n_paintball(x3) & (x1 = x2) & n_people(x1))
exists e1 x1 x2 x3 x4.(a_topic(x1) & in(e1,x4) & n_paintball(x4) & Theme(e1,x3) & v_participate(e1) & (x1 = x3) & of(x1,x2) & n_co-worker(x2) & n_group(x1))