[ALUG] nfs mounted directory ownerships

Hi all, I have a central directory owned by user 'balloon' on my server. This can be nfs mounted onto serveral other computers, each with a user 'balloon'. However, the server UID for balloon is different from that of the clients. I'm reluctant to start changing things in /etc/passwd. Is there an elegant way to state the nfs mount with username permissions rather than number? Thanks, Jenny