For the actual Windows 7 and XP -Yes you can "multiboot" to Windows XP and Windows 7. *(After installing Windows 7, default Windows 7 is selected and that will be the primary choice for booting to Windows 7).
See the following detailed instructions on the Microsoft website: http://tinyurl.com/ycqbde4
Essentially, these are the important steps to pay attention to:
"On the Which type of installation do you want? page, click Custom.
On the Where do you want to install Windows? page, select the partition or disk where you want to install the new Windows operating system.
Be sure to install Windows on a different partition from the one where the earlier version of Windows is installed.
Click Next to begin the installation. You might see a compatibility report."
Additional information about Multiboot from the Microsoft website:
Can I have more than one operating system on my computer (multiboot)? http://tinyurl.com/yccnt22
Let me know if this helps!
Microsoft Windows Client Support