yes, ths is possible and there are programs which can help you do this, or Windows already includes the ability by editing the MSDOS.SYS file on your machine. Similar file should be included with XP, i am not positive on its naming since XP no longer requires DOS. So this file would be missing, but you can edit it under your 98 box with notepad if you want to see what it looks like.
The alternative way would be to use a boot loader.
Extended Operating System Loader (XOSL) is the world's only full-featured free boot manager with a real, easy-to-use and full-blown graphical user interface.
The link is not working as i write this so dropping an alternative link for the program.
http://www.icewalkers.com/Linux/Software/5...14550/XOSL.html
By installing Windows98 and Windows XP on the same partition you can easily control and save space as well. You do not ( should not have to) install each to a seperate partition, but I am not positive on this anymore. I used to have Win95 & 98 installed on the sme partition, as well as NT4 & 98 on the same partitions.
Some more freeware bootloaders
http://btmgr.sourceforge.net/about.html
http://gag.sourceforge.net/
http://www.dirfile.com/freeware/partitions.htm
MSDOS.SYS
http://www.computerhope.com/msdossys.htm