Sharing /usr, what about subdirs?

[x]

I want to share /usr between all distro's on my computer, as well as with RedHat on another machine.
This shouldn't be a problem, but there are a few subdir's I know have to take care of: /X11R6 & /local, I'll have to create a link here as these are "distro-specific". Are there any other? When I look in /usr I find some that I'm afraid are not shareable; /bin, /include, /lib, /libexe, /sbin & /kerberos. Can I share them or do I have to link these too? And - most important - when I want to share a directory, is there any way I can find out if it's possible or not?

[pbharris]

hello,
i have my fstab file to indicate that the other directories are there but not mounted under /usr, but deb_usr or rh_usr depending upon which distor i am using at the time. as for NFS edit the file /etc/exports and indicate which directories are okay to be accessed and by whcih machine.