If I have an xml file :-
.
.
<?xml version="1.0"?>
<!DOCTYPE root-ele [
<!ENTITY ele2-replace SYSTEM "ele2.xml">
<!ELEMENT root-ele (ele1,ele2)>
<!ELEMENT ele1 (#PCDATA)>
<!ELEMENT ele2 (#PCDATA)>
]>
<root-ele>
<ele1>Test1</ele1>
&ele2-replace;
</root-ele>
.
.
/*----file = ele2.xml-----*/
<ele2>Test</ele2>