A group of people are gathered at some type of outdoor event.
A group of people are outside.
If people were gathered outside then there doesn't seem to be an organized event taking place, just a gathering.
exists e1 s1 x1 x2 x3 x4.(at(e1,x3) & of(x3,x4) & n_event(x4) & a_outdoor(s1) & Theme(s1,x4) & n_type(x3) & Theme(e1,x1) & v_gather(e1) & of(x1,x2) & n_people(x2) & n_group(x1))
exists s1 x1 x2.(Theme(s1,x1) & a_outside(s1) & of(x1,x2) & n_people(x2) & n_group(x1))