There are a few ways to do that. Personally, I prefer this one. because it’s gives me the best control over the shape and position of the blend edges, as well as the least amount of control points:
You may also try manuallt building some simple 4-sided surface with 4 control points total whose two edges are relatively close to the target surfaces. Then, rebuild the surface to degree 5 with 6 control points and use “Match surface” with the “CurveNearSurface=On” option. That will let you match the surface edges directly on the target surface rather than its edge.