The church has always had target ministries. Missions is a target ministry. Paul was specifically directed by God to target the Macedonians. Philip was taken away from a productive ministry to target one Ethiopian!
The problem is when a target ministry becomes so inwardly focused the people lose their relationship to the whole body of Christ. Small Groups are great target ministries in a church, but the whole body still should come together once a week so that everyone gets to know others who aren't part of their little group. Otherwise things tend to fly apart after awhile.