def dict_diff(dicts):
    """
    Subset dictionaries to keys which map to multiple values
    """
    diff_keys = set()

    for k in union(set(d.keys()) for d in dicts):
        values = []
        for d in dicts:
            if k not in d:
                diff_keys.add(k)
                break
            else:
                values.append(d[k])
                if nunique(values) > 1:
                    diff_keys.add(k)
                    break

    return [dict_subset(d, diff_keys) for d in dicts]