Joins & Relates to ESRI Hosted Data for ArcGIS Online

[LanceCase]

I have a project where I need to classify ZIP codes to 4 levels of nested groups (similar to nested hydrologic units).  Rather than download a database of ZIP codes, add my classification, and upload them to ArcGIS Online, it would be great to join my table to an existing ESRI hosted dataset that is already uploaded and optimized for rendering online.  In other words, I would like to link my table to and existing dataset already published. 

I don't think this is already possible, but would love to hear otherwise or add this to a my dream list of functionality.

Thanks,

Lance

[DanCraver]

My organization has this same need.  We have enterprise hosted feature layers managed by our national office that individual field offices need to join their additional attributes to (stored in standalone tables). The additional attributes are unique among offices, often unique even within an office depending on the subset of enterprise data.  We do not want to promote making copies of the enterprise layers.

A solution would be saving the join output as a hosted feature layer view, but the creator has to be owner of both the target (enterprise) and join (table) layers.  We need our field staff to be able to own and manage these views while the national data manager owns the enterprise spatial data.