Enforce Dependencies Between Optional Elements?

[Anthony Watson]

For the below xml schema section, is there any way to say that the 'remote-ejb-home' element is required ONLY if the 'ejb-version' element is present?

<xs:element name="object">
<xs:complexType>
<xs:sequence>
<xs:element ref="ejb-version" minOccurs="0" maxOccurs="1" />
<xs:element ref="remote-ejb-home" minOccurs="0" maxOccurs="1" />
<xs:element ref="jndi-name" minOccurs="0" maxOccurs="1" />
<xs:element ref="context-name" minOccurs="0" maxOccurs="1" />
</xs:sequence>
</xs:complexType>
</xs:element>

Thanks a lot in advance