Combine faces to create single face

Hello,

 

I want to turn the outside of this object(red) into a single face, is this possible?

 

For a bit more context, I want to use the curved pattern feature and intersection curve within solidworks API. These functions require a face to normal to. The image below shows what the intersection curve currently looks like. The sketch seperates on the corners which makes it difficult to use within VBA.

The fit spline function can fix the sketch, but only when done manually. I think the solution to this is combining the faces, but I don't know if that is possible.