Ok you need a small partition at the begining of the master drive(C:) formatted in FAT, this will hold all the dos programs and the start files for the other operating systems i.e. Autoexec.bat for 98 and Ntldr Ntdetect.com boot.ini for XP and MSdos.sys, IO.sys Command.com etc. for DOS.
The boot loader (menu) to allow you to select which op system will also be on this partition
then two more seperate partitions to install both 98(fat32) and XP (NTFS).
takes you through the procedure.