Network options

Hi all, I'm pretty clueless when it comes to networking, so need some advice to see if I'm on the right track.

I have a room that has 3 computers, 2 with no wireless, 1 has it, but gets poor signal.

I would like to be able to transfer files between these computers at a decent rate. Internet speed isn't a huge issue, as I'm on a pretty slow connection.

I can't run ethernet cables to the room, as the walls are solid blocks with no gap between. A cable would have to come through the roof & down the wall, which isn't an option.

So I was thinking I could use an ethernet over power adapter to connect the modem/router to a gigabit switch connected to the computers in the room.

Will this work ok?

if the power outlets are on the same breaker circuit that should work