join with

join (someone) with (someone else)

 and join (something) with (something else)
to connect things or people. I joined Fred with the others. We joined the older puppies with the full-grown dogs.
See also: join

join (up) with someone or something

to bring oneself into association with someone or something. I decided to join up with the other group. Our group joined with another similar group.
See also: join