I have 2 powerline adapters (model TL-PA251) happily paired for the last 5 years and now wish to add 2 more. I'm looking at 2 TL-PA4010PKIT adapters. Will these be compatible and what exactly would I need to do to add them successfully please? I'm thinking of using one to replace the older adapter serving the router and using the other for my son's Xbox. The one currently serving the router is as I said already paired with the other TL-PA251. Would I need to indevidually re-pair the 2 old ones and the other new one to the new one that would be connected to the router?