[Leica] Focus Magic question

[pklein at 2alpha.net (Peter Klein)]

I've been trying Focus Magic out today.  After a bit of experimenting, I'm 
a believer.  I was able to touch up some slightly misfocused or 
motion-blurred old Kodachrome scans from the 50s, and the difference is 
remarkable.

But not only that.  I've found that a small application of Focus Magic to 
digital camera pictures seems to sharpen them cleanly and recover a bit of 
detail. It appears to do this better than unsharp mask or in-camera 
sharpening. With less artifacting and less "fake digital" crispy-crunchy 
look.  A big thank-you to Sonny Carter for getting me thinking in this 
direction.

Picture Window Pro is my image editor, and it doesn't run Photoshop 
plug-ins.  So I've been running the Focus Magic plug-in out of 
Irfanview.  In Irfanview, the processing is applied to the entire image--no 
selection is possible.

Which leads to my question:  In Photoshop, can you apply the Focus Magic 
plug-in through a mask?  The purpose would be to use it to sharpen the 
in-focus portion of the picture only, leaving the rest untouched.  Or, to 
apply a small "blur width" to the subject, then reverse the mask and do a 
second pass to bring a slightly out-of-focus background into better 
focus.  Is this possible in Photoshop, PS Elements, or other plug-in 
compatible programs?

Thanks!
--Peter