1
general::
Connect closely with, coordinate, as in They are trying to tie in the movie promotion with the book it is based on, or His story does not tie in with the facts. [First half of 1900s]
American Heritage Idioms
2
general::
Phrase(s): tie in(to something)
to fasten or connect to something. • Can you fix it so my computer can tie into Rachel’s? • This one will not tie into her computer., Phrase(s): tie in (with someone or something)
to join with someone or something; to connect with someone or something. (See also tie in with something.) • I would like to tie in with you and see if we can solve this together. • We would like for you to tie in and share your expertise.
McGrawhill's American Idioms And Phrasal Verbs