thanks so much for this @njyo!
very much appreciate it, and it does indeed a) clarify (simplify 
) and b) extend / deepen ‘the issue’. which is indeed a complex one –especially for non software- and network-architects like me…
so, you got me blushing two times:
one, for getting right to the core.
You want to see which Whiteboards an Entity is embedded on. Is that correct?
Entities do have a field that showsReferenced x times, which shows the Entities, where a link has been placed. If I gather correctly, you would like to also see the Whiteboards listed there. Would that solve one of your challenges?
– correct! yes, it would splash my main concern. (– plus, I didn´t know about the ‘referenced x times’. thx for bringing that up also.)
second time you red-faced me was by linking to a thread that asks (proposes) the very same thing, and is preceding my inquiry some days… 
– I didn´t find that at the time, so am sorry to have ‘forked’ this… 
then, Schema Tables
yeah! If I understand this correctly (as, again, I am coming from content / concept work contexts not real systems architectures), this would be fabulous.
And indeed I´d see that as on topic, given the extended version of it here in the thread.
For one, it really sounds like another extension of representing complex relational logics into entities themselves, making them even richer…
… and then, I think – again, if I understand correctly –, it brings some thing to the table (sic!) that was certainly part of my thinking, elaborations and musings: it sounds like it is a data-table like ‘device’ to represent heterogeneous relations of entities in one complex field; like a matrix.
this is important, as basically the ‘conept maps’ I am talking about (or however one wants to call the visual modelling plane, aka 'whiteboard) are sheets visualizing / registering / establishing heterogeneous relations between entities. (so in my current working example a ‘concept’ (entity) could be simultaneously linked to: ‘parent concepts’, ‘lateral (sibling) concepts’, ‘children’, … but also to ‘paradigms’, ‘issues’ etc.
so many heads up for you clarifying and enriching all this, with some nice (but unnecessary 
) modesty on top…! 
PS: and, excuse me producing so much ‘discourse’ around it, and extending to all the rather private methodological, philosophical, cognitive models that I am covered in… but, actually, just the addition of this idea of ‘schema tables’ seems to have made all this worth it for me! 
