This sounds like a pretty standard multitenant datastore. Everything has a user/group Id on it, and a logical layer that locks a connection to a specific group.
FoundationDB is really just a set of structures and tools to build any type of database you want on top of a solid foundation.
"FoundationDB decouples its data storage technology from its data model. FoundationDB’s core ordered key-value storage technology can be efficiently adapted and remapped to a broad array of rich data models. Using indexing as an example, FoundationDB’s core provides no indexing and never will. Instead, a layer provides indexing by storing two kinds of key-values, one for the data and one for the index."
Then existing standard layers like the Record layer, providing "(very) roughly equivalent to a simple relational database" providing structured types, index, complex types, queries, etc.
Yeah, the advantage or difference here is that these "layers" are a common design pattern with FoundationDB, several ship in FDB by default, and you're encouraged to make more, so the database certainly has better support than just adding a column for TenantID, but still you're right that it's not too out there.
