splitting a large file into entities

[Cheryl Chase <cheryl@isna.org>]

I am working on my first project in docbook. I've just split my file  
into multiple files, with the content of each chapter represented by  
an Entity contained in a separate file.

Is there a way to associate the docbook dtd with each of the Entity  
files so that they can be edited independently?

Thanks,

Cheryl