"Stepsisters" can be replaced with a variety of synonyms depending on the context. Some possible options include "blended siblings," "family amalgam," "kin by remarriage," or "marriage-related sisters." Alternatively, one could use more general terms such as "family members" or "relatives" if the specifics of the relationship are not relevant. In some cultures, there may also be specific terms for step-siblings, such as "soukan kyoudai" in Japanese or "madheen" in Arabic. Overall, the choice of synonym will depend on the desired tone and level of specificity in the text.