Boundaries are a natural thing that form when one group finds more connectivity with another group and gravitates towards them. Most notably, race and wealth tend to play a huge factor in societal boundaries. The wealthy tend to think that they are above the lower classes because they have a superiority complex, and so tend to gravitate towards far more expensive properties to create a financial boundary between themselves and the lower class. And since living spaces tend to have differing geographical locations, the wealthy and the poor create a boundary between themselves. In Winter Park, the wealthy side of the town costs more to live on, and so the rich gravitate towards that area. The wealthy also have a desire to keep the poor out of the neighborhood, in order to attract other wealthy people to live nearby, to create a wealthy community. This superiority complex and diference in wealth creates the largest of boundaries between people in a community.
The wealth difference also creates a difference in culture. Usually, the wealthy can afford the best education, and a higher form of entertainment and understanding of higher level concepts. The wealthy culture tends to focus on forming a higher educaton to lead to success, meanwhile the lower classes have less money, and so their culture instills the state of mind that focuses on earning money early to help the family rather than getting a good education to recieve a better job later on. Also, it dooms the lower class to poverty because higher learning, such as college, usually is expensive, and so only the wealthy can pay for it. In essence, the financial difference creates not only a physical seperation due to property cost, but also a dfference in culture that is very difficult for the lower class to overcome due to their financial situation.
Another issue is race, but I believe that race is more closely tied to finances. In the grand scheme of things, the issue of racial segregation and discriminaton has only been eliminated for close to a few generations. Until the late 1960's, racial discrimination tended to create a very difficult financial situation for most African American families. They tend to be in poorer areas because racial segregation is still having a lingering effect, and it may take a few generations to shake off the poverty effects. Also, race is very closely connected to culture. And, as previously mentioned, cultures that are similar tend to gravitate together even more so than cultures that are based on financial situation. So, race as a boundary is more a matter of lingering segregation, financial situation, and culture mixed into one.