The latest generation of Powerline Ethernet adapters are out- literally, they just came out - and they have better performance than whatever you are using now because of MIMO and more bandwidth available due to the full use of the electrical lines. Just replace the ones you are using now with the new 1200 adapters and put a good, robust Gigabit Ethernet switch in the office to handle the Server and anything else you want to put in there. Problem solved. I just bought a bunch of Netgear GS208 switches off of Amazon for $25 a pop and am putting them in every room, where I have just installed the latest Powerline Ethernet adapters. They have large buffers, jumbo frame support, and the performance you need.