Adding domain accounts on local computers
I will advice that you add the users of the network to the local area network domain so as to be easy to manage them. You will configure their accounts in that for a user to access the network and use its resources they will need to identify themselves to the network by providing details like usernames and passwords. You can also do this for the users who are outside the network range so that when they need to use the network too they access it using the credentials you have provided.
Doing that will help you control the users of the network when it comes to usage of bandwidth and bandwidth allocation, and also help you protect the network from unauthorized people who may want to snoop and use the network resources for free.