The rugby players play on a field.
A group of rugby players practices outside.
Since fields can be indoors, it does not necessarily follow that they are outside. That they are playing does not imply they are practicing.
exists e1 x1 x2 x3.(n_player(x1) & of(x1,x2) & n_rugby(x2) & on(e1,x3) & n_field(x3) & Actor(e1,x1) & v_play(e1))
exists s1 s2 x1 x2 x3 x4.(a_topic(x1) & Theme(s2,x4) & a_outside(s2) & (x1 = x4) & Time(x1,x3) & n_practice(x3) & of(x1,x2) & n_player(x2) & a_rugby(s1) & Theme(s1,x2) & n_group(x1))