First, I would say that most people's first experience of living with people would be living with their parents. Therefore, most people's first experience of living with other people would be living with someone other than their parents.
That said, I think we need to be careful not to overanalyze simple example sentences from a dictionary. Your question reminds me of people who debate whether we have ten fingers or eight, because maybe a thumb isn't "technically" a finger. Most people can figure out such technicalities through context.
In the right context, we can usually figure out which group "other people" refers to. In the context of living in a house, "other people" often means people outside of their immediate family. In another context, though, it might mean something totally different. For example, in a school, "other people" might refer to the staff:
Ted: We need to survey the faculty and see if they are happy with the new school policies.
Ned: Not just the faculty, we should survey other people too.
In that context, "other people" might refer to custodians, lunchroom cooks, office secretaries, etc.