DITA 1.3 supports cross-deliverable addressing which is documented via OASIS here: https://docs.oasis-open.org/dita/dita/v1.3/os/part2-tech-content/archSpec/base/links-between-maps.html
“DITA processors are not required to resolve key references to peer maps. However, if all resources are available in the same processing or management context, processors have the potential to resolve key references to peer maps. There might be performance, scale, and user interface challenges in implementing such systems, but the ability to resolve any given reference is ensured when the source files are physically accessible.”
However, we've explored DITA 1.3 in Tridion Docs 14 and we have found that this is not currently supported. The functionality is not yet implemented as part of DITA-OT. Here is the forum thread that discusses this issue. We would have to write a DITA-OT plugin that does some processing of the content so hyperlinks could be added to a different publication. The last comment on that thread has a link to a plugin that provides cross-deliverable linking on HTML5-based output formats. I think we would have to do something similar for dynamic delivery output formats in Docs 14.