Yosef Karo

“ A priori, one should not do more. They required both a partnership and eruv in the time of the Gmara when the residents of the yard did not give to the partnership; rather, the yard made an eruv for itself and one member of the yard gave to the partnership. However, in our situation when everyone just makes one partnership, if one does extra and blesses on it, it is a wasted blessing (his own opinion and the Responsa of the Mahara"m brought by the Beit Yosef) . ”