The Collaborative International Dictionary of English v.0.48:

Ghettoize \Ghet"to*ize\, v. t.
   to form into a ghetto; to isolate (people) as though into a
   ghetto.
   [PJC]

WordNet (r) 3.0 (2006):

ghettoize
    v 1: put in a ghetto; "The Jews in Eastern Europe were
         ghettoized" [syn: ghettoize, ghettoise]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "ghettoize":
   bolt, cordon, cordon off, cull out, divide, gin, insulate, isolate,
   keep apart, keep aside, lay aside, pick out, put aside, quarantine,
   riddle, screen, seclude, segregate, separate, set apart, set aside,
   sieve, sift, sort out, thrash, thresh, winnow