I don't see why this isn't possible...
This should help you to get a boot disk working:
http://www.linuxjournal.com/article.php?sid=4622
These are the instructions I followed after the FC2/XP dual boot problem blitzed my machine.
Get the grub boot floppy working first. I think the command you need is "configfile" to get the GRUB menu configured.
Once it is working, you should be able to create a bootable CD from the floppy image (consult your CD-writing software on how to do this)
Once you have it working to your satisfaction (and have of course backed up your hard drives

), remove GRUB from the MBR by booting from your XP CD , go into the XP recovery console and type "fixmbr", or get hold of a bootable DOS floppy that has fdisk, and enter "fdisk /mbr"
The machine should now boot directly into XP, or display the GRUB menu from the CD/floppy.