Yosef Karo

“ Paragraph 4 - If one person lives in the inner yard and one person lives in the outer yard or two live in the outer yard but they made an eruv, the individual in the inner one does not render the outer one forbidden. ”

“ If one is forbidden to use his own place, he can render another forbidden from using his place if he walks through it, but if one is permitted to use his own place, he cannot render another forbidden from using his place if he walks through it. ”