BGW 320-5050 hooking up Uverse box
I have fiber coming to a BGW320-5050. From there it's hooked up via Ethernet to a router on the other side of the house, which feeds Ethernet jacks in various places around the house, including one that feeds my Uverse TV. In that connection there are 3 cat5 Ethernet connections - (1) wall to Netgear router 5, (2) Netgear 2 to Uverse box "Network", (3) Netgear 3 to TV "LAN", plus Uverse box HDMI to TV HDMI. This has worked great and much better than when I had it using WIFI.
This week I tried to add another Uverse TV in the room where the BGW320 resides. Unfortunately there's no Ethernet back to my home run closet, so I tried to connect it directly to one of the other Ethernet ports in the BGW320. I tried the same setup, except the equivalent of (1) above going from a BGW320 Ethernet port to a different Netgear router. This doesn't work at all. First of all, it didn't successfully connect well to the Uverse box (which I thought could be a problem with the box), but also it causes the original tv to lose connection. It'll work for 10 seconds before stalling out. If I change the channel it'll work for another 10 seconds before stalling out, etc.
So apparently this is not a valid way of connecting this situation. Is there a good way of doing this without having to resort to WIFI? thanks