The Collaborative International Dictionary of English v.0.48:

Sectionalize \Sec"tion*al*ize\, v. t.
   To divide according to geographical sections or local
   interests. [U. S.]
   [1913 Webster]

         The principal results of the struggle were to
         sectionalize parties.                    --Nicolay &
                                                  Hay (Life of
                                                  Lincoln).
   [1913 Webster]

WordNet (r) 3.0 (2006):

sectionalize
    v 1: divide into sections, especially into geographic sections;
         "sectionalize a country" [syn: sectionalize,
         sectionalise]