<xs:group name="DerivativeSecurityListElements"> <xs:sequence> <xs:element name="Undly" type="UnderlyingInstrument_Block_t" minOccurs="0" /> <xs:element name="RelSym" type="RelSymDerivSecGrp_Block_t" minOccurs="0" maxOccurs="unbounded" /> </xs:sequence> </xs:group>