In those cases where the Secretary determines that the jurisdictional provisions of
section 1911(a) of this title are not feasible, he is authorized to accept partial retrocession which will enable tribes to exercise referral jurisdiction as provided in
section 1911(b) of this title, or, where appropriate, will allow them to exercise exclusive jurisdiction as provided in
section 1911(a) of this title over limited community or geographic areas without regard for the reservation status of the area affected.