What happens if there are three consecutive yards, and the outer two merge with the middle yard but not with each other: Eruvin 45b, 46b, 48a-49a, 71a, 91a
Separately merging an external set of areas, and an internal set of areas, laid out such that the internal dwellers must pass through the external area to reach a public area, where they both use the same path penetrating the outer area and running in to the inner area: Eruvin 59b, 65b, 66a, 73a, 75a
Merging houses which are adjacent to each other, where the last house opens into an alley or yard, and is the only Jewish house opening into that alley or yard, so that the residents of these houses will be able to transport property into that alley or yard through the last house's entrance: Eruvin 74b-75a
