How to see an NT Intranet Server on Netw

I work in a school and I am setting up an Intranet server running NT on the network. What I want to know is how to set it up so users on the two existing networks (Admin and School Users) can see the Intranet. The Admin network is on a different IP and Subnet range than the School Network, I have setup the Intranet Server so that it is on the same IP and Subnet as the School Users Network so they can all see it but I also need users on the Admin Network to be able to see it. At the moment I have trust relationships setup between servers but thats all. Can anyone offer any advice ?