For me, eternal families means we are linked by covenant to our Savior Jesus Christ. If we are truly spiritually reborn, then Jesus Christ becomes our spiritual father in the eternities. We become part of His eternal family, He becomes our God and our Father. The sealing link in the Temple, links us back to Him. So to be an eternal family to me means that I belong to His family, that I choose by covenant and the fulfillment of that covenant to become even as He is. To be an eternal family means living with my spouse the life that the Savior lives, becoming as He is, fulfilling His plan for His children, my brothers and sisters and all that goes with that. It means I and my wife become one as together we become as He is and thus as our Heavenly Parents are, and progressing, growing through exhaltations as we continue together to become as they are, to live the life they do, to do what they do.
I find it interesting that though we know of the kingdoms and who goes where, and so forth that there has to be more to the plan than that which is revealed. I sat in a meeting once where Neal A. Maxwell and Rex D. Pinegar went through the the plan of salvation and when they came to the three kingdoms of glory, both Elder Pinegar and Maxwell explained that what we know is what goes on to that point. Elder Maxwell pointed to the sealing ceremony and reminded us that kingdoms, thrones, principalities, powers, dominions and exhaltations are all plural and inform us that there is more to the plan beyond what is openly revealed, that there is a continuation of the plan and for us to become even as the Father and the Savior will take ions . . . and then he paused, stopped, and said to paraphrase, that is not for public teaching and we won't go into that. It is enough to know that we must gain the highest degree of glory in the Celestial Kingdom for now." He teased us that yes, there is more to the plan, but it is not one of those things the Lord allows to be discussed to those who are not ready for it. He then focused on what we need to be doing in the here and now in order to qualify ourselves through the atonement to continue to progress and come back into the presence of the Lord.
I have my own personal opinion what it means to be part of an eternal family and what the plan is for those who obtain the highest degree of the celestial kingdom and what it means for those that don't. However, I do agree, now years later, and after many experiences and further mentoring with the Lord, with Elder Maxwell that the here and now is focused on exercising faith unto repentance, learning to draw upon the powers of the atonement, thus yielding my will and heart and mind to the Savior's and then striving to fulfill His will in service to my spouse, my family and to others and in thus serving them, gain the experiences that I need in order to move step by step to becoming even as He is. To be honest, it isn't just what I need to learn, that is part of it, a lot of it is what my spouse and I need to learn to become together that I think matters perhaps a little more as we place Him in the center of our personal lives and our lives as a couple.