RBR750 adding wired satellite to my Mesh Network

I purchased the RBK753s Mesh System. Came with (1) router and (2) satellites. I need to now add 2 additional exterior locations that are roughly 75’ and 100’ from the router. Both locations I ran high speed network cable and would like to keep all devices on same WiFi without having to select a different network. What can I purchase that helps me achieve this goal? Or my I forced to but routers? Looking for best suggestions.