So I have the 3 X50 Decos, main one connected to the ISP modem, then a switch and other 2 Decos wired via the switch.I'd like to add another Deco unit in a nearby room, where I don't have a LAN cable from the switch. Could I connect this new unit to the other one via a LAN cable directly?

It'll be something like this. Will this work, or all decos must be either connected via switch or only between them?

Thanks