extracting a 2D plane from a 3D FITS image

Hi. Is there a way using the cfitsio "extended file name syntax" to
extract a 2D plane from a 3D FITS image? I see how I can do other
sorts of slicing, like extracting a cube from the center of a larger
cube. For instance, I might do something like:

file.fits[20:50, 10:40, 15:55]

to end up with a cropping of the original cube. I also know that I
can do something like

file.fits[*, *, 23:23]

which will result in a one voxel thick 3D FITS cube, which is almost a
2D image. But I realy want to get rid of that third dimension
altogether, not end up with a very thin third dimension.

Also, I want to do this using the cfitsio extended file name syntax --
not a separate program.

Thanks!
|oug