919. Two Residents Who Do Not Join an Eiruv
Eiruvin 2:3
If the residents who made the eiruv forgo their ownership rights in favor of the one who did not participate in the eiruv, he is permitted to carry because he is now the sole property-owner and the others are not permitted to carry because they no longer own property. We do not say that they are considered guests of the one resident because, halachically-speaking, the many cannot become the guests of the one.
Eiruvin 2:4
If two or more residents do not participate in the eiruv, then if they forgo their ownership rights in favor of the other residents, those who made the eiruv may carry and those who did not may not. Those who made the eiruv cannot forgo their ownership rights in favor of the other two residents because each of them restricts the other’s ability to carry. Even if one of those two forgoes his ownership rights in favor of the other person, they are still not permitted to carry since he was not permitted to carry when the others ceded their rights to him. If there are two residents in a courtyard and one resident makes an eiruv, he may not forgo his ownership in favor of the one who did not join, but the one who did not can forgo his ownership in favor of the one who did.