This is a subject that can get convoluted very quickly, especially in the culture of redefinition that pervades modern Western society. My efforts to clarify will be seen as insensitive and that is because so many people believe that calling a situation something that it is not is a high virtue. I believe such references help create deceptive alternate realities that disorient well-meaning yet naive people away from exalting truths.
As a prelude, I want to say that I do not discount the power of friends and associates in helping each of us to pursue good and even righteous paths. The structure of the Church of Jesus Christ of Latter-day Saints, as ordained by God, is that of an intentional community. Communities and their members can do much good for each other and I do not seek to denigrate such contributions that affect the lives of people in positive ways. For instance, the "building up of Zion" as a community is an over-arching purpose of the Church and fulfills prophecy proclaimed by the Lord and his servants that helps will be forthcoming in bringing ourselves and others to God.
It is always with a bit of apprehension that I hear proclamations from Latter-day Saint pulpits, even from the one at the conference center in Salt Lake City, where members praise their "ward family". [A "ward" is a congregation defined by geographical boundaries.] For me, such a term and idea strikes a sour tone. However, this concept and its kindred thought of the congregational bishop as the "father" of the ward is beloved by many in the Church and will be patiently defended by members and leaders, small and great. I think it would be a better path if we made the effort to excise such concepts and phrasing from our minds and focus more strongly on the revealed truths of the eternal nature and promugation of actual families.
I can immediately think of two ways that God can directly influence individuals: through sending certain souls to join their family and removing people from situations through death. We know that Diety frowns on our toying with these two things - prohibitions on taboo actions like abortion and suicide throughout time are plain in holy writ. Meddling with God's perogative over life and death is a sure way to stir God's wrath and forego hope for a glorified afterlife. Until one sees the peril in interfering in divine influence, somewhat equal punishments for murder and adultery seem unjust. God takes his role as master of life and death very seriously and severely punishes any who presume to impinge on it.
I has become fashionable to redefine what constitutes a "family", now mostly along the lines of an assemblage of people you like and find most comfortable. In the not too distant past, this definition was far more relevant to intentional communities as refered to above. Everyone knew that you couldn't choose your parents or siblings, but you could and should choose your friends. The new-fangled attitude that "family" was little more than a collection of friends contributed heavily to the idea that one could depart an unhappy "bio-family", through divorce or disowning, without any real consequences and forge other connections (albeit situationally fluid) that should be honored (legally at least) just as highly or often moreso than the traditional family. From my perspective, these re-defined "families" are at the heart of much of the degeneracy that sharply weakens our society.
For the purposes of this writing, I will only address one facet of God's perogative: childbirth. Parents cannot choose their children like products in a grocery store or like favored friends: a child comes predominently as the result of external forces over which parents have little control. I believe it can be accurately said that the children born to a couple are God's choice and contribution to a family. The natural or "God-given" family, where children are brought into it by birth, is the manifestation of God's direct and intimate influence in the lives of most people. As a result, choices to bear and raise children in ways prescribed by God and the decision to face the often "rocky road" that such parenting presents are among the prime examinations used to determine one's eternal outcome. Heaven dictates such deep tests in life and if one decides to try and "game" the tests through "redefining" themselves and others, there is quite literally hell to pay, as Lucifer and the third of spirits who followed him can attest.
To establish a community as a substitute for family is to interfere in God's business and purpose. The Church of Jesus Christ of Latter-day Saints is a highly structured community of communities (wards) designed to help families fulfill their divine destinies of linking all of us together and to God. The God-given family is the important thing here. There is no ordinance that binds a ward or grouping together in the eternities as there are for families. There is no sealing event that ties you to a local bishop or leader in either life or death as there are such ties to mother and father. No matter how wonderful the people who sit on the pews near you on a Sunday morning are as a community, if they are not members of your sealed family, they can serve only as tangental helps to your journey, valuable though such help can prove to be. For Latter-day Saints, their local congregation should be seen as a community and their bishop as something akin to a mayor or constable, performing a valuable community function. One can love community leaders very much, but not so much as to regard them in the same (or better) stead as one's natural parents. A bishop should never presume to substitute for a father and we should never look to him in that way. It denegrates God's act of assigning you to your mother and father through birth.
Family is the central exalting entity throughout eternity, chosen and sealed together by God. Your affinity community, religious or not, can help you toward whatever purpose upon which you and they agree and for as long or short a time as mutually desired. I hope you can see the large difference between the two and refrain from getting them mixed up ever again.