Plex on a boat with no internet and multiple users

I have a Plex server on my boat. 99.9% of the time we have no internet. Currently it will work for one person (using no login) in but nobody else can view anything else simultaneously. Is there a way of being able to have multiple clients operate at the same time with no internet? Server is Windows, clients are using the iPad app but I will be using RasPlex on Samsung TVs soon.

Thanks,

Ian