Question On STR usage attribute

<xsd:attribute name="Usage" type="xsd:QName">
		<xsd:annotation>
		<xsd:documentation>This global attribute is used to 
		indicate the usage of a referenced or indicated token within the containing 
		context</xsd:documentation>
		</xsd:annotation>
	</xsd:attribute>

Does the definition of the usage attribute of STR allow for the
association of multiple usage annotations with an STR?

I think the way it is defined, you can only associate a single value,
which itself may represent a combination of usage concepts, as long as
someone has gone to the trouble of enumerating the particular combination
you are interested in.

Of course this question presumes that there is or will be a use case that
requires that multiple usage annotations be associated with an STR.

Ron