Linking DITA Topics Through Relationship Tables
DITA provides a powerful means of linking using relationship tables. The benefit of using a relationship table is the ability to create and maintain links in one place with the map rather than in the topics. Links can be created both between topics of the same information type and between topics of different information types that are not directly related through parent/child relationships. Therefore, the best practice for linking in DITA is to use a relationship table within a map.
Bruski, Kylene. Center for Information-Development Management (2005). Articles>Information Design>XML>DITA