take a look at the multichain-node package. I use it quite often (and even used it for inspiration for some of my own tools). I believe in the original package there is a way to use a connector file, where you put your connection information. All users connect to your node application, and the node application uses the local (or remote) chain node to communicate with the chain.
Or you could make some kind of initialization script that downloads multichain and attempts to connect to your main node.
I'm sure you can come up with something to notify an administrator like yourself to give out the connect permissions to the addresses