The easiest thing to do is run the printer EITHER ethernet OR USB.

Set up a network with all computers AND the printer connected to the network hub/switch/router. 

I have a similar setup at home, with four (sometimes five) computers all sharing three printers, including one ethernet printer. 

If the printer is not ethernet, you can connect it to anyone of the computers and let that computer be a "print server" for that printer. You have to have a "home" or "office" network configured, and then enable "sharing" for that printer. Then you can "add printer" from any other computer on the network and find that printer.