How to establish and maintain traceability links between requirements, work items, and other artifacts using IBM DOORS Next Generation and IBM Rational Team Concert
One answer
You add associations in the project areas you want to link between: https://www.ibm.com/docs/en/engineering-lifecycle-management-suite/lifecycle-management/7.0.2?topic=client-adding-associations
Once you did it, you can link items using the editors Link areas/sections.