Windows 2000,XP,Vista on ONE HARDDISK?

I have windows 2000 and Windows Vista on my pc, after I install Vista, boot screen shows only two options

1. Older Version of Windows
2. Windows Vista

When I select 1. Older Version, Windows 2000 is loaded, I dont find any option to start Windows XP,

OS are installed in following order
1. Windows 2000 (E drive)
2. Windows XP (D Drive)
3. Windows Vista (c Drive)

Is there anyway for me to start Windows XP? or Vista support only one earlier Windows operating system?

Thanks in advance