Most of the year I use Multiplicity 4 Pro to access a headless computer and a non-headless laptop in the same room, but I travel (preparing today!) and still use MP4 Pro to access computers from 700 miles away!
"Multiplicity" should really be named "Multiplicity KM" to avoid confusion - a KVM version is needed when monitors on the primary computer are to be used to view the remotes. I am emphasizing what basj wrote in this regard.
"Hello, a question with Multiplicity, can I control computers that are not within the same network"
No - the computers must be on the same local area network. However, they do not have to have addresses on the same physical router. My computers have 2 LAN addresses: one is assigned by the router, the other is assigned by a virtual network "router". There are several virtual network products available: I use Zero Tier. When I am 700 miles away, the addresses assigned by routers places my computers on different, inaccessible, networks. However, the Zero Tier virtual LAN allows me to connect just as well as when I use physical router addresses. I just have to tell Multiplicty to change to the other LAN address.