1. A method, comprising: storing, at a router, at least one neighbor table that stores one or more Border Gateway Protocol (BGP) neighbors of the router, each BGP neighbor corresponding to at least one virtual routing and forwarding (VRF) instance and associated VRF identifier (ID), the at least one neighbor table indexing the BGP neighbors according to their respective VRF ID; initiating a BGP update generation for a BGP table having one or more BGP network entries to be advertised, each entry having an associated VRF ID that indicates to which VRF instance the BGP entry is to be advertised; in response, performing a single lookup operation into the neighbor table for each BGP entry based on the corresponding VRF ID of each BGP entry to determine a corresponding VRF update group of indexed BGP neighbors to which each BGP entry is to be advertised; and generating a shared BGP update for each VRF update group for the initiated BGP update generation.