One of the properties of human relationships is that they are messy, inexact, and complex. We should not expect to find one perfect way to group or cluster a network of human relationships. If we do find such a perfect solution, maybe we have over-simplified the problem…
Finding logical and plausible clusters in complex systems is not a simple task — there is no one simple answer. This is not like accounting, where everything should add up correctly every time, and you do get one right answer. Finding clusters in networks is often about sense-making, what are the logical patterns we see and what might they tell us? In our human relationships, we always want “neat and clean”, but we always get “messy and fuzzy.” The right software will help you through the messy, and help you make sense of it — it will not provide simple answers.