Control visibility of nested Detail Family

This topic has been addressed multiple times on this forum but I can’t seem to find the answer to my specific challenge (if there is any).

I have a Generic Model Family (A), with inside amongst others a nested Detail Item Family (B). It functions as a symbol in Plan Views. My top goal is to be able to turn B on/off in the project using something that I can trigger in a View Template (so not using Visibility Parameters inside A).

– To ‘reach’ B from within a project the nested Family should be set to ‘Shared’. However it is not possible to load a Shared Detail Item Family inside a Generic Model Family (error message:  While loading “B”: Shared detail components cannot be used in 3d model families.).

– The things inside B that I would like to control are Filled Regions so I can’t use Subcategories (or I have to turn off Detail Items all together, but that conflicts with other items in my Plan View).

– I thought about hiding/removing B and using Tags as an alternative, but those can’t be rotated 270 degrees without weird things happening to the layout of the Tag.

– Nesting B inside a Generic Annotation Family would lead to scaling issues in differently scaled Plan Views.

Does anybody have a golden idea what I could try next?