Yosef Karo

“ We bless "to finish the Hallel," whether with the community or alone. We do not interrupt during it except for the ways that are done during the reading of the Shema: in the middle [of a section] we greet somebody who we fear and respond to somebody who we respect, and between the sections we greet somebody who we respect and respond to anybody. If one interrupted in the middle with enough time to say it all, they do only need to return to the place that they stopped. ”