I have a scenario where I have one subform that is included in multiple main forms, and I'm looking to somehow link them together. If I try to add bidirectional lookups to the subform based on the existing relationships - I can only choose one at a time - so it only works for one main / sub relationship.

Ideally I would have a single 'Source' column in the subform that is linked to the main forms that were used at the time the subform rows were added. The goal is to have a report on the subform where I can see all subform rows and also see where/how each row was added.

Any ideas?