Target ministries are good and biblical. Paul led a specifically gentile focussed church. Even Jesus specifically focussed on reaching out to Jews. Even the twelve had the fishing group and the tax collector group. In each of those examples however, there were exceptions.

Reaching out to certain people in certain ways is strategic and sensable. Singles may be more likely to come to an event where they can meet other singles. Any oppotunity to set up a sinner with the saint who will eventually lead them to Christ should not be missed.

A youth group can be more vibrant and exciting with lighter, interactive teachings. Working groups can deal with issues like reaching out to people in the workplace. Student groups can offer Godly advice for a person's studies. Undoubtably, a combination of small groups with a specific focus in combination with Sunday services involving the larger church community and allowing interaction between people who may not normall sociallise is a good way to meet both specific needs and general needs.