Because we are gay, bi, or lesbian, we are not tied to any particular flow of patriarchal structure, or are the end of such a structure-by-blood-relation. We don't produce from our uteri (if we have any such thing), and we don't give grandchildren to our own parents. We may adopt and raise children, but not much else.
Thus, we are tied together into family units by the people with whom we have sexual relations and share our personal resources. Because the potential for a biologically-patriarchal relationship in the form of "birthing-parent-over-birthed-child" is absent from a same-sex relationship, we are relatively free to share our sex, our love and our care with more than one other person. The same-sex relationship is defined primarily by the intimate interaction between two or more peers, regardless of age.
But how does same-sex polyamory become solidified into a house? Since we are not "breeders", but are mostly childfree by default (unless adoption comes into play), the need to construct family life around the birthing, raising and nurturing of children doesn't appear as a default component in the equation of the same-sex family, including the same-sex polyamorous family.
Instead, in the matter of a same-sex polyamorous relationship, the main focus will be directed to non-biological areas of familial interests, including the successive lordship and responsibility over the estate of the same-sex polyamorous family (which may be less or more convoluted, depending upon the size of the polyamorous family).
A same-sex polyamorous family may be more inclined to settle in rural/rustic areas, as a greater number of willing partners in a marriage contract (or, in heterosexual polygynous relationships, a larger number of wives and children) usually tends to equate with rural settlement (same-sex Communes being a good example); in opposing cases, those who identify as single and childless tend to reside within urban and suburban areas. The settlement in rural areas would also be a setting for the development of a distinct gay rural culture.