Schema validation question

[Linda Grimaldi <grimlinda@earthlink.net>]

I have been out of the XML world for a little while now, but someone just asked me a question and I have to admit, it's going to keep me up tonight if I can't come up with a better solution.  And I'm a little rusty, to boot...

The issue is one of data dependency and validation.  The goal is to enforce a restriction on pairs of data values- if the data associated with the node <Fruit><Name> is "Apple", then the value of the sibling node <Fruit><Abbrev> must be "APL".  Effectively, the goal is to enforce a specific mapping from one enum into another within an XML document. The only way my associate could figure to capture this dependency is as follows:

<xs:complexType name="Fruit">
	<xs:annotation>
		<xs:documentation>Defines the valid values for fruit types</xs:documentation>
	</xs:annotation>
	<xs:choice>
		<xs:element name="APL" type="xs:token" fixed="Apple"/>
		<xs:element name="ORG" type="xs:token" fixed="Orange"/>
		<xs:element name="BAN" type="xs:token" fixed="Banana"/>
		<xs:element name="LEM" type="xs:token" fixed="Lemon"/>
		<xs:element name="GRP" type="xs:token" fixed="Grape"/>
	</xs:choice>
</xs:complexType>

All in all, this strikes me as a very ugly, even offensive, solution.  My initial response was to forget about the validation- it wasn't worth it.  Is there a way to preserve the data dependency validation without warping the instance document as the above schema fragment would require?

Thanks,
Linda