<xs:group name="MarketSegmentGrpElements"> <xs:sequence> <xs:element name="SecTrdgRules" type="SecurityTradingRules_Block_t" minOccurs="0" maxOccurs="1" /> <xs:element name="StrkRules" type="StrikeRules_Block_t" minOccurs="0" maxOccurs="unbounded" /> </xs:sequence> </xs:group>