smoothing only part of an object

[Billabong]

I am really stumped on this. Is there a way I can smooth only part of an object without it affecting the rest of the object, In the image I included, notice how the green line flows from the front to the back, I want to smooth that curve so the edges wont be visible in a render, If I use turbosmooth, then im going to have make a hundred cuts and such just to get the edges back in my windows. Which is the only way I'm familiar with. I'm sure you can do this with the Subdivision surfaces, but that means I have to and make sure all corners are in a different smoothing group then the rest, which will take forever, and i if do have to do it this way could please explain how, im not that familiar with the Nurms subdivision. is there an easier way of doing this without adding a lot more geometry? Thank you for any help.

 

[notamondayfan]

try chamfering and smoothing groups (f1)

[Billabong]

I tired the different smoothing groups, but it gave me this weird shading

 

[only3d]

personally id start with a curved spline to begin with and go from there but since u probably dont want to give up what u done so far, how about adding only that part and then just welding it to the rest? seems like the simplest and least hassle way to do it imo.

[Billabong]

thanks only3D thats what Ill probably end up doing