You can always uninstall office, copy the contents of the cd to your hard drive. Something like,
c:\officecd
Install from there, not the cd. Take the cd out. Do that on each machine. Now everytime it needs the cd it'll look under c:\officecd instead of d:\ or whatever your cdrom drive is, so it won't even need the cd for it.
There's a setting in the registry you could change, but not sure where it's at. If you look for it, it'll say something like installpath d:\
Just change d:\ to c:\officecd or where ever you copied the office cd to, and it won't ask for the cd anymore, because it'll just copy whatever it needs from your c:\officecd path.