Someone take a look at my Alias Model

I just stared to study Class A technical surfacing modeling for Alias Automotive. Im trying to make a model of the A5 but having trouble making rear blend. I need the rear C pillars to blend with the rear trunk in curvature. Am I approaching this wrong or whats the deal? Every time I try to create curvature continuity following the C pillars the blend will go abruptly. Any Ideas?