I'm making the assumption that this: "I can access it fine from my iMac" might imply that you have installed WordPress on that particular machine. If that isn't the case, some more details may be required.
You would probably need to assign the machine where WordPress is installed a static internal network ip address. Example: 192.x.x.x
Replacing all references to "localhost" in the addresses in your WordPress database with the new internal ip address, should then make it accessible from the rest of the machines on your own network.
In order for WordPress to continue being accessible from the machine where it's installed at this point, an additional entry might need to be manually placed in the machines host file that would resolve 127.0.0.1 to the static internal 192.x.x.x