No the point with iges is, that the curves pass in.
But this is not what concerns groups.
Anyway i want to point out that, currently it is good enough,
just wonderful groups could pass in too.
I mean : geometry is okay, but the grouping information, that is an important aspect in upcoming Moi3d and fundametal in Houdini,
could be not ignored or just displaying names, that is: groups are empty at current state.

And one more aspect with iges file format. Houdini exports also its curves into iges and they come very well into Moi3d also.