SAP Mobile Platform 2.<x> includes the concept of synchronization groups and relationships between MBOs. You can configure the client code to synchronize only specific synchronization groups. SAP Mobile Platform 3.<x> provides similar functionality with the OData query option $expand.
The $expand option relies on navigations that specify how to move between OData entities that have an association. In NetWeaver Gateway, you implement how data is retrieved during navigation, by creating an association set and assigning it to an association.