I worship in a large church organization, which would be the antithesis of the type of organization I believe the first century Church looked like. Nevertheless, we seem to be able to solve the unity problem through the use of many small groups within our large local church membership. Through these little temporary structures we seem to be able to rejoice with those who rejoice and weep with those of us who weep.
I am not qualified to offer answers for the dilemma of John 17:11, but I believe I am able to testify about what I have experienced – or what I’ve found that seems to work, and what I’ve seen that does not work. The fruit of the Spirit, love (Galatians 5:22), doesn’t seem to arise often out of large groups. Once we begin to try to tie two or more local church bodies together, competition seems to be the inevitable result. Which church will be the leading body of believers? Whose pastor will be the ‘first among equals’? If there is to be a superintendent or bishop over all the linked church bodies, who will that be, and from which of the local bodies will he come? It seems that no one wants to be second; no one wants to be last; each one seeks to be of some importance (Mark 10:37; Luke 22:24; cp. Philippians 2:7). Moreover, the entity created (i.e. the organization resulting from uniting two or more church bodies) seeks to preserve itself, often at the expense of love (Matthew 16:25; cp. Galatians 1:10).
On the other hand, small groups that are created within the local church body of believers are formed with the idea of service in mind. Bereavement groups are formed with the specific idea of sharing one’s sense of loss with others who are going through unspeakable emotional loss. No one is seeking to be great in these circumstances. The whole focus is on helping those who are in pain.
Another small group formed for the service of others that I’ve seen is one of common talents. Great fellowship can be found in using one’s talents with others of like talents, such as cooking for those who are sick, home repairs for those who can’t afford to have it done, or those who can afford only the cost of materials. Serving is the idea, reaching out to be last by lifting up those in a weaker position and placing them first. In the meantime, those who are doing the serving, not only receive a great reward within their spirits, but also find good friendships they didn’t have and great fellowship while working together in an expression of love in the Spirit.
Sunday school groups and Wednesday night Bible study groups are other forms of service within the larger local church body. Although there is a greater temptation for some to be the greatest teacher or to lord it over the faith of other believers, the predominant idea is to share one’s faith with folks who want to do the same. If done correctly, all grow in the knowledge of God and in the strength of the Spirit and in friendship toward one another. The individuals within each group grow closer together in love and pray for one another’s needs as expressed within that specific group.
The groups are often temporary or membership within specific groups is temporary. Those grieving over the loss of a loved one eventually find the strength they need, from the love of others within the group, and are able to move on with a positive outlook. Some friendships gained will remain, but the needs are satisfied. Sunday school groups and other Bible study groups disband after the subject at hand is discussed thoroughly, and the believers form other small groups created around other subjects. Those that don’t disband are usually populated by different individuals wanting to discuss the same subject the previous believers found helpful or interesting. Moreover, as groups are disbanded, and the same believers form different groups, all of these groups are seen as a way to provide each believer with an ever larger circle of believing friends and acquaintances within the larger church body.
Additionally, the groups are not seeking to preserve their own existence. If the interest isn’t there, they are disbanded. The groups are formed to serve real people in need or having a common interest. When the Spirit of God influences the individuals of the group, the group is helpful and serves a general concern. Once the common interest is satisfied, the group is disbanded and/or the individuals move on to other groups of interest (or not) as seems to fit the desire of each believer. As a rule, no one is seeking to be first, but, if that rule is violated, the small group will be disbanded in due course leaving the one seeking to be first without a constituency to gratify his competitive desires. While I am not qualified to tell anyone that small groups are the answer to ‘unity’ as expressed in John 17:11, I do see these groups as very helpful to the believer and generally promote unity within the local church body.
 As I said HERE, this current theme about the person of Jesus is based upon the book: The Jesus Style by Gayle Erwin. They are my thoughts about his book. He may or may not agree with the impression his book has made upon me, but I thoroughly enjoyed reading what Gayle wrote and recommend his book to anyone who is looking for a good read about Jesus.