Bidirectional lookups with 3 or more forms

Bidirectional lookups with 3 or more forms

Per the attached, I have 3 forms.

My "main" form is PU, which has a unique field in it called PU_ID

My two other forms contain PU-related data: PU PGIP and PU Data.

I have bidirectional relationships established between PU and both PU PGIP and PU Data using the PU_ID field (which in itself was an odd experience - more below).

However, when I want to create a report based on PU PGIP, I can't pull fields from PU Data because (of course) those two forms aren't directly related.

My questions are:
  1. What is the best practice for relating 3 or more forms so I can seamlessly pull data from any of the forms into any report related to the various forms?

  2. Am I seeing this correctly, in that in order to create a bidirectional relationship, a second field always has to be created to hold the related data? (This is not the case with a simple unidirectional lookup, which holds the data in itself)
Tagging Damien and the folks at bcCloudTech, hoping for their input.

Thanks!