This is the query language we use to group for one of our subnets. you should be able to modify the last line with the subnet and wildcard to show all systems.
select SMS_R_System.Name, SMS_R_System.SMSAssignedSites, SMS_R_System.IPAddresses, SMS_R_System.IPSubnets, SMS_R_System.OperatingSystemNameandVersion, SMS_R_System.ResourceDomainORWorkgroup, SMS_R_System.LastLogonUserDomain, SMS_R_System.LastLogonUserName, SMS_R_System.SMSUniqueIdentifier, SMS_R_System.ResourceId, SMS_R_System.ResourceType, SMS_R_System.NetbiosName from SMS_R_System inner join SMS_G_System_NETWORK_ADAPTER_CONFIGURATION on SMS_G_System_NETWORK_ADAPTER_CONFIGURATION.ResourceID = SMS_R_System.ResourceId where SMS_G_System_NETWORK_ADAPTER_CONFIGURATION.IPAddress like "xx.xx.xx.%