Share Office2000 – 2 OS’ on 1 machine?

I have 3 partitions on a hdd. dev1 running XP Pro, dev2 running 2000 Pro. How can I get the two os’ to share one installation of Office 2000 Pro? I don’t have enough hdd real estate to do two installations and I can’t seem to figure out how to export the CORRECT registry settings to import them into the other os’ registry. HELP! This is somewhat critical as I seem to keep crashing XP Pro somehow and use 2000 as my reliable backup. PS The Office installation is currently placed under the XP install.