A method includes determining all telephone numbers to which a selected CLLI can terminate calls, wherein the CLLI is associated with one or more major trading areas (MTAs), creating a FROM-TO relationship between at least a subset of TNs in the one or more MTAs and the TNs to which the selected CLLI can terminate calls, and provisioning the FROM-TO relationship on a core routing engine accessible to a switch. A system includes a local route manager (LRM) configured to receive input designating a CLLI as available for intra-MTA routing, the CLLI being associated with one or more MTAs, a cluster generator configured to create a first set of all telephone numbers (TNs) handled by the CLLI, a second set of selected TNs in the one or more MTAs, and an association between the first set and the second set, and a provisioning module configured to provision the association between the first set and the second set on a core routing engine to identify calls between TNs of the sets as local in jurisdiction.