Change files indexed for Data Structures / annotated.html page

Hi all,

When generating documentation, I have header files dedicated to Doxygen 
comments and also header files for the code base. Initially I removed 
the header files that contained code from the indexing so as to only use 
the doxygen comments. This seemed to cause an error when generating the 
'Data Structures' and 'annotated.html' page. How would I go about 
changing what files that are indexed for this page?

Thanks for any help,

Ethan