This is not an exact answer to your question, but I have touched on restaurants in the Soviet Union in a previous post.

To tie it into your question more directly, the upper echelon of the Soviet elite would frequent a Georgian restaurant in Moscow, Aragvi, and it actually led to the Georgian SSR increasing their economic ties with Moscow, to the point that food production and export came under the purview of the NKVD (precursor to the KGB).