In a LAN of about 20 boxes, the "server" has to give each "client" a turn at becoming the server.

What I mean is that in this NFS/NIS system each "client" needs to have at some stage some of its directories and files readable by all other clients as well as the server. This includes some files located on this client as well as some of its files located on the server.

This has to be enabled & disabled from the (real) server, through a browser if possible.

Is there a simple clean way to implement this? If not what's the cleanest way to do it?

Any hint most welcome.