Help setting up dual boot & hiding partitions

I'll try to keep this as short as possible but still have it make sense

Basically I need to find a way to setup 20 machines that will be dual booting 2 copies of Windows XP Pro SP3.

1 version of windows will be a stripped down OS connecting to domain controller with heavily restricted profiles meaning minimal access to settings etc.
The other version of windows will have to be just a standard install, not joining a domain and with no restrictions.

So far so good I've not got too many problems doing the above.

The bit I need help with is that when booting into the unrestricted OS, both partitions are visible meaning that files on the first partition can be edited. So I need to find a way, either with a free boot manager or something, of getting partition 1 to load windows and hide partition 2, and vice versa when loading partition 2 hide partition 1.

Any recommendations or suggestions would be greatly appreciated.