The world of Lannisteria is is broken down into separate realms known as the 7 kingdoms. These inner planes exist in separate dimensions called realms, and are separated from each other. Along with these continents are smaller landmasses that exist alongside them in dimensions called demi-realms. These are smaller worlds that are each tied to a larger realm as satellites. A realm can have several satellite realms or a few hundred.
These continents are interconnected through the use of portals, which can be used to travel between worlds. However, demi-realms are not capable of traveling to other satellites directly. They must travel to the main realm first in order to get access to any of the other demi-realms. Even if the demirealm of their destination is a satellite of their own realm, they would still have to go through this process in order to reach it.
This is ridiculously time consuming and expensive. Going to a satellite next to you on the geographically cosmic plane would be a shorter and cheaper journey if direct travel occurred. However, attempts to rectify this have failed. Having to use the main realm just to get there is like going from New York to New Jersey, but having to go through Beijing.
How can this be the case even if satellites are next door to each other?