<xsd:complexType name="RMC"> <xsd:sequence> <xsd:element ref="RMC.1" minOccurs="0" maxOccurs="1" /> <xsd:element ref="RMC.2" minOccurs="0" maxOccurs="1" /> <xsd:element ref="RMC.3" minOccurs="0" maxOccurs="1" /> </xsd:sequence> </xsd:complexType>