polarize (one group of people) into (two groups of people)
To cause a group of people to divide into two opposing or contrasting groups. The issue has polarized the country into two bitterly divided camps—those in favor of the legislation, and those against it. The controversial CEO tends to polarize employees into a group that loves him and a group that hates him.
polarize something into something
to divide a group into two segments. Your actions have just polarized the students into two opposing groups! We polarized the entire population into two factions.
See also: polarize