Internet Access Using Multiple Computers On Private Wireless Network

the site has a private wireless network for which I pay a yearly access fee. This gives me a code I can use to gain access each time I connect. We used to be able to have all our family's laptops, etc., connected at the same time using this code, but the site has recently changed the configuration so that we can't do this. Is there any way we can share the connection made by one computer so that we can all access the Internet at the same time? The site is in a remote location that gets poor mobile data coverage and landlines are not an option. The yearly fee is already high, so I can't afford to pay for multiple subscriptions.