Assuming that multiple devices are in the same general location a multi-port powerline adapter is not needed. A single port powerline adapter will work just fine.
Spend $15-$20 dollars on a 4 port gigabit switch and connect the switch uplink to the powerline adapter. In fact most switches are smart enough to know that the device being addressed is on the switch and it sends the data between switch ports. Without sending it through the router.
Another side affect of this is that if you are using a Roku and tablo on the same switch and all the devices have have been assign addresses by DHCP if the router goes down the Roku can still function with the tablo on the switch. When you start the tablo app on the Roku you get the popup menu indicating the internet is down with the option to proceed. If you proceed the tablo app functions properly. Or at least it did two weeks ago.
Of course the app popup message of the internet being down seems to be a clear indication the Roku apps phone home on startup if they can.