从中

play tricks in secret; make mischief

hinder/prevent sb from doing sth; place/hedge obstacles in the way; create difficulties; make trouble

play the part of go-between/matchmaker

profit from; cash in/capitalize on; make capital out of; reap unfair gains from; seek one's own gain out of

draw a lesson from

mediate/arbitrate/intervene between (disputants, adversaries, etc)

mediate between (two sides/parties); mediate from among (them); act as an intermediary between

make a choice among; choose from

play the part of a middleman

benefit from

make a profit for oneself (in a deal); profit from; profit thereby

make political capital (out of sth)

throw a spanner into the works; throw a monkey wrench into the works