The best way to get back at someone else is too ignore them. Why waste time, theirs or yours, by allowing them to occupy your valuable real estate (your body or mind). It’s time to evict them from your property and if they are not part of your success-oriented team; let them go. As in the Frozen movie-Let It Go.
It’s okay to remain friends with the opposing team, just don’t let them rain on your parade and steal the ball (your dream) from you.