Loft is a method of creating surfaces in Rhino. The output of the Loft command is a surface. “Loft” is not a type of Rhino entity.
All Rhino surfaces have four sides, though one or two sides can have zero length. Rhino surfaces can be trimmed at the edges and holes trimmed in the middle, but the underlying surface still has four sides.
You could try Drape or Patch but if the resulting surfaces a close to conforming to the input curves they may have too many control points to efficiently modify.
You could also create some curves between the circles and the outer boundary, divide the overall surface into several surfaces and then use Sweep2, EdgeSrf, or NetworkSrf to create the individual surfaces, MatchSrf can be used to adjust how adjoining surfaces meet. Rebuild or FitSrf may need to be used before MatchSrf.