How do they release their co-wives? [If] a [man's] daughter, or [any] one of these forbidden relations, was married to his brother, and he had another wife [as well], and he died —- just as his daughter is released, so too is her co-wife. If his daughter's co-wife went and married his second brother, and he [also] had another wife, and [then] he died —- just as his daughter's co-wife is released, so too is her co-wife's co-wife, even if there are a hundred.  How is it that if they died their co-wives are permitted? [If] a [man's] daughter, or [any] one of these forbidden relatives, was married to his brother, and he [also] had another wife, and his daughter died, or was divorced, and then his brother died —- her co-wife is permitted.  Anyone who was able to refuse but did not do so —- her co-wife requires chalitzah but is prohibited from yibum.