Does each Service Group have its own IP and DiskGroup?

Usually, Service Groups have their own IP and DiskGroup resources, but this is not technically required; it all depends on your applications. All a Service Group really needs is some resource. Most resources, however, cannot be shared across Service Groups. That is why Service Groups usually do have their own IP's, DiskGroup, filesystems, etc. Groups can share certain resources like NIC and MultiNICA, although the resource has a unique name in each Group.