Exploring Extremes of Nationalism

While the concept of patriotism has interesting components, I find myself desiring to explore nationalism further.  Probably due to the intrigue created by chaos and disagreements that I often mind myself attracted to.  Anyhow, we talked in class today about nationalism being based on ideals in subculture in addition to countries.  What are the boundaries of nationalism and who determines them? When an nationalist organization is created, does the opinion of the "leader" determine the primary parameters of the specified group or do the majority opinion decide?  If a group is created in support of women's' rights, for example, is the enterprise exclusive to accepted members?  Would men be allowed if they supported the cause?  These questions falsify the stability of nationalistic ideals, in my opinion.  How can one respect or understand the basis for groups that are unregulated in selecting their aspects?  On a different note, how does this support for subcultures impact the totality of our universal culture? Is there a truly universal culture, or do we ascribe culture based on general assumptions about characteristics of the masses. If a person is not at all patriotic or nationalist do you consider them contributing members of their respective country or cause?