Yosef Karo, Translation:Shulchan Aruch — Orach Chaim 374…
“ Paragraph 3 - If there is a small yard whose wall is mostly breached before Shabbat to a large yard and the breach is not more than ten amot wide, it is permitted for the residents of the large yard to take objects from the house to the yard if they made an eruv for themselves. It is forbidden for the small yard to take objects in the house to the yard unless they made a joint eruv. ”
