Combining Two Cable Drops to Create a MOCA Network

I have a Roamio Pro and an older Series 3 HD. I would like to create a MOCA network for them. However, I noticed that Optimum gave me two drops - one for the phone and internet and a separate one for the digital tv. I read an Arris article showing how it could be done. I would need to eliminate one of the drops. Which drop should I use and what kind of high pass filter should I use to prevent back flow of noise? Would an HPFO-54MHz found on Ebay or an electronic parts site work?



Thanks.