Using a Mac Mini to create a second wifi network

Hi

In my condo block we have a shared wifi network.

Id like to make a private network in my condo without paying extra.

Mac mini only has the one built in wifi chip.

Im wondering if i could buy some kind of usb wifi dongle and then use one to connect to the condo wifi and one to make a "new network" which only I have access to.

Then i can connect all my devices via wifi to the mac mini on my "private network", share printers and files securely. And the main connection connects to the condo wifi. All devices on my private network should have access to the internet obviously.

I was thinking to do this with a hardware wifi bridge, but ive realised because theres a problem as the condo wifi diconnects you after an hour of no activity. So basically i have to keep a computer on with a "keep alive" script/app running to stop it disconnecting. When its disconnected you have to go to the condo web page and enter password again manually. So basically i think the device i use as the "bridge" has to have some kind of keep alive thing on it. So im thinking to use Mac mini. Is it possible? I dont really want to keep a power hungry noisy PC running 24/7.

Thanks