Corel to Microsoft Office conversion

I’ve read some of the previous posts on this and I can tell this will be a headache but here goes;
We’re converting 4000 users from Corel(version 8,9, 10) to Office 2000 & XP.
Is there any utility/software that we can use to convert the Corel documents to the Office format?
Any input as to how, where to look, etc would be greatly appreciated.
Thanks,