The phrase "be one family" implies a close bond and unity among individuals, and there are several synonyms that convey a similar sentiment. One synonym is "united," which suggests an unbreakable alliance and a shared purpose. Another alternative is "connected," which implies a strong interpersonal relationship and an emotional tie. "All in this together" is another synonym, which highlights a collective effort towards a common goal. "Solidarity" is also a relevant synonym that emphasizes support and cooperation. Ultimately, all of these synonyms convey the idea of a group working together towards a common cause and striving for a sense of belonging and camaraderie.