The following is a link to a presentation by Primavera in which it talks about "link categories" which I should find under Plan/Links/Link Categories/User Fields. Problem is that I do not find the tab "Links" under Plan. I am using PRA 8.7.56. The feature was added at version 8.2. No mention of it being removed at My Oracle Support. Any suggestions? This might be an interesting feature to explore.
https://docs.google.com/viewer?url=http%3A%2F%2Fwww.rdcpm.com%2FRelationshipDrivenCPM.pdf [1]