Yosef Karo

“ Therefore, there is a custom to gather a bit of flour from every house in order to make one loaf that will be the eruv (the Magid and Hagahot HaRaava"d chapter 1 from the laws of Eruvin) , and this is the custom in these countries. One should be careful that the loaf fulfills the measurements detailed below in chapter 368 paragraph 3. Even if some flour is left over and all of it is not made into bread, it is still an eruv, because this is no worse than if one person makes the eruv for everyone. ”

“ Paragraph 2 - Those who dwell in tents, booths, or camps that are surrounded by a wall cannot carry from tent to tent until they make an eruv. However, a caravan that is surrounded by a wall does not need an eruv, as they are all mixed and their tents are not permanently theirs. Rem"a: Houses in a boat need an eruv, even if the boat has walls. ”

“ Paragraph 8 An eruv can be made with rice or lentil bread, but not with millet bread.
סעיף ח - מערבין בפת ארז ועדשים, אבל לא בפת דחן.
Paragraph 9 - If one of the residents of the yards wants to give bread on behalf of everyone, this is better, as long as he confers possession of the bread to everyone using another person. When he transfers possession, he must lift [the bread] one tefach from the ground. He must transfer possession to all of the residents of the yard or the alley and to everyone who will join from this day on. ”