959. The Status on an Alley in the Absence of a Shittuf
Eiruvin 5:15
If eiruvs have been made between the courtyards and their houses but a shittuf was not made, then carrying something more than four cubits (about six feet) in the alley is prohibited, the same as in a carmelis (the quasi-public domain). Since eiruvs were made between the courtyards and their houses, the alley is considered opened to the houses but not to the courtyards. Accordingly, we may not carry within it. If the residents of the courtyards did not make eiruvs, they may carry things that were in the alley when Shabbos began all throughout the alley, the same as one may do in a courtyard when an eiruv has not been made.
Eiruvin 5:16
The procedure to be followed when one of the residents of an alley is not Jewish or is a Sadducee is the same as when a non-Jew or a Sadducee is a resident of a courtyard. The Jewish residents must rent the non-Jew's property in the courtyard from him or from a member of his household; a Sadducee must forgo ownership rights to his domain. If a Jew and a non-Jew are the only residents of an alley, a shittuf is unnecessary. The same procedures apply when many residents rely on one household for their meals.