For people who like the same things, their opinions should match as well.
People who like the same things should have matching opinions too.
「好きな物が同じ人同士」→「People who like the same things」
「意見」→「Opinion」
「合う」→「To match, matching」
まとめて言いますと、
「For people who like the same things, their opinions should match as well.」
「People who like the same things should have matching opinions too.」
と表現します。
どちらでも使えます。
シンガポール 
