merge in (to something)
to join into something. The stream merged into the main channel of the river.
merge someone or something into something
and merge someone or something into route someone or something into something else. They merged the marchers into the parade and no one ever knew they were late. We merged in the latecomers to the parade at an intersection.
merge (something) with (something else)
to join two things together. The management merged the sales division with the marketing division. We merged the accounting department with the auditing department.
merge with someone or something
to join with someone or something. Ted merged with Fred and they created a very profitable partnership. Our company merged with a larger one, and we all kept our jobs. This stream merges with a larger stream about two miles to the west.