Dear Mickey Koth,
Regarding the web page "Entry element for Spanish and Portuguese surnames" (http://www.library.yale.edu/cataloging/music/spanport.htm), I'm afraid the example used by Ellen Jaramillo to highlight the difference between Spanish and Portuguese surnames is a bad one. The Spanish Castillo Blanco also happens to have a well-known equivalent in Portuguese, written and indexed in the same order as in Spanish: the compound surname Castelo Branco (sometimes hyphenated), as in the famous Portuguese Romantic writer, Camilo Castelo Branco. (Incidentally, it's spelled Castelo, or Castello in its older form, not "Castelho.")  A different surname example pair (such Juan López Rodriguez/João Rodrigues Lopes) would, therefore, have been much better suited to your purposes.

Pedro Vieira