The exact functionality isn't available, but I expect you could do the following:
1. Create links between DOORS objects and DNG artifacts; Show the links to artfiacts in DNG in their own column in DOORS [A]
2. Use ReqIF to bring the data into DOORS, then use native DOORS features to display them.
3. Explore using the Rational Engineering Lifecycle Manager (RELM) to display both DOORS and related DOORS NG information

Notes
[A] If you plan to use the new configuration management capabilities in DOORS NG currently in the 6.0 beta, then (1) probably isn't your best choice. Once artifacts in DOORS NG are being used in multiple streams and baselines, the links to DOORS 9 will be a lot trickier to maintain correctly.
[B] See the Jazz.net blog or your favorite search engine for more info; also track progress by the Jazz Report Service Report Builder team to support DOORS data (DOORS NG data already supported).