952. Residents Who Are Partners
Eiruvin 5:1
If the residents of an alley are business partners in a certain food, such as if they bought wine, oil, honey, etc., then they need not make another shittuf to enable carrying on Shabbos. Rather, they may rely on their existing business partnership. This is only the case when their business partnership involves only one type of food, which is kept in a single vessel. If their arrangement is that one of them has wine and another has oil, or that they both have wine but they keep it in different vessels, then they must make another shittuf for Shabbos purposes.
Eiruvin 5:2
If one residents of an alley asks another for wine or oil before Shabbos and the second person refuses to give it to him, the shittuf is canceled because the latter revealed that he doesn’t really consider them partners with equal rights. If one resident of an alley who typically participates in the shittuf fails to do so, the other residents may enter his home and take his contribution toward the shittuf against his will. If a resident of an alley refuses to join a shittuf, he may be compelled to do so.