Is it possible to program additional parameters to the Grasshopper Network Surf command to have an additional input node (or two)?. The additional input node would be for surfaces whose edge curves are the U or V curves already plugged into that network surf command. It seems like Grasshopper simply needs to realize that some of the curves that you are using to create the network surf came from other surfaces and were not isolated curves.
I’m simply comparing the process to Rhino. In Rhino, you only click on the curves you want, but if you click on a surface (for which you have already extracted an edge curve) then Rhino will pop up the mini-dialog box asking you to pick whether you want to choose the curve or the surface edge. All you do is choose the surface edge rather than the extracted curve and you get the tangency continuity.