People gathering outside of a conference or dinner room.
the people are all on the bus
People gathering outside of a room can not be on the bus.
exists e1 x1 x2.(a_topic(x1) & (exists x3.(of(e1,x3) & n_conference(x3)) | exists x4 x5.(of(e1,x4) & n_room(x4) & of(x4,x5) & n_dinner(x5))) & r_outside(e1) & Actor(e1,x2) & v_gather(e1) & (x1 = x2) & n_people(x1))
exists p1 x1 x2.(n_bus(x2) & n_people(x1) & r_all(x1) & on(x1,x2))