including another xml file (without a DTD)

Hello.

I have a big XML file I would like to split up into smaller XML files. I know that this can be done using an entity inside a DTD:

<!DOCTYPE novel SYSTEM "foo.dtd" [
<!ENTITY bar SYSTEM "bar.xml">
]>

But, I am using Schemas.  Is there still a way for me to do this?

Thanks.

Follow-Ups:
- Re: including another xml file (without a DTD)
  - From: Michael Kay <mike@s...>
- Re: including another xml file (without a DTD)
  - From: "G. Ken Holman" <gkholman@C...>