Trying to keep an un patched surface

hi everyone I’m finishing a model for work and would like to have surfaces complete with no joins where possible!
this might be just a fixation but as I am now working mainly on Rhino I would like to be able to blend the two corners shown and keep a unique surface on the main body of the car.
I blended them and then duplicated the main surface, I then cut out the angles in the duplicated surface so that the surface would be perfect but in reality i now have 3 surfaces rather than one .
Is there a better way to do this, I believe i can do what I want to do bit it will be no doubt a long way around and I can’t always afford! to waist time doing it my way.
can anyone help?

thanks in anticipation

Can you post a file with the surrounding surfaces (not the whole thing if it is confidential) or send to, to my attention, I’ll take a look. Better to post here if you can, more feedback…


Thanks Pascal I’ll get that sorted as soon as I can, probably tomorrow