NFS questions

If I want two computers to share the same user information would I just
blow away the /usr partition by mounting a nfs partition named /usr ?
what about /etc/passwd and /etc/group ? Do you usally just copy them
over or link them somehow? I suspect many of these questions would
proably be easier if I just did it then saw what happened (burning
complete backups now) but I thought I'd ask around first (and at least
*feel* safer) <g>

Carl Parrish