Linking xml files together

Hello all,

I try to find a solution for the following and hope I can get some ideas
here.
What I trying to do is the following:

First file:

	<root>
		<node>
			<id value="test"/>
		</node>
	<root>

Second file:
	<procedure id="test">
		<sequence>
		...
		</sequence>
	</procedure>

The actual result would be that the id node is replaced with the sequence
node. I could do this by means of XSLT, but I wonder if there is no other
way to reach this. Can I construct my xml that way that I do not need to
implement the functionality in my code, but instead my XML Parser knows it
has to replace that piece of xml file. I already thought about entities but
XML schema does not seem to support entities.

Any help is welcome.

Kind regards,
Ismaël