Home Network :: How To Manage Data Sharing In A Little Intranet On Windows

I should set up a network for a little enterprise.The requirements can be summarized as follows:

- All the "business" softwares have to be stored in a single computer (let's call it "the server"). The other computers (in this case there should be at most 2 or 3 computers) can execute these softwares through the server. So there are no local copies of those softwares on clients, only on the server.
- The main computer (the server) shares also a printer.
- All the computers in the network, are interconnected through a single wi-fi modem/router. Some of them are connected through the wi-fi interface and others through an ethernet cable.

the server, in order to perform some special procedures, has to connect to a special modem which connects it to a remote private network. In order to do so, the server disconnects from the local enterprise network because Windows does not allow me to stay connected to more than one network at the same time.The remote private network does not require to disconnect from any other network, it's just a constraint imposed by Windows.In the meantime, clients are not able to execute softwares anymore and cannot print anything.when the server is connected to the private network, it still needs to execute the "business" softwares.

Is it possible to keep the server connected to both the networks without denying the access to softwares, data and printers to anyone? If yes, how?If not, how can I design the topology of the network in order to share softwares and other data among all the computers (server and clients)? It's important that when the server connects to the private network every computer (including the server itself) can still access softwares, data and printers.