Portal Binding

Portal Binding is the act of involves binding one or more portals to the structure that becomes a demesne's main source of transportation.
It involves the agreement of multiple wild portals, and a portalsmyth that is trusted to get those wild portals to work together in the formation of the primary portal that services an area. As one wild portal is tied to one particular path from one location to another, in order to have a portal that will take you to multiple locations, it will involve multiple individual wild portals either being forced together to work as one unit or encouraged to work together to the same result.
As in most things, portals where the individual Wilds aren't coerced into working together make for a more productive structure, but it is only in a more recent time where this has been fully understood.
In the beginning, they worked that way as much out of the personal portalsmyth's inclination rather than understanding what the full result would be. During the middle period, more out of haste than out of any malicious desire to mistreat the entities they were using to get from one place to another, they forced the issue more freqnently than they might have done otherwise, with a few notable exceptions. Only later, when the system started approaching collapse in some sectors, was the damage done during this rushed period understood, and the few active portalsmyths made the effort to try to undo the damage that had been done.

The Ritual

In the beginning, before anything else can be done, there has to be a structure that can hold them.
Most of the time, the structure containing them is made out of a stone archway, although more modern structures like the network that exists in Stiwen has found other materials work as well. Wood is not a material that would weather time and the stress of frequent transports well enough to be used as a long-term solution, but as a stop-gap to keep a Wild Portal from wandering until a more formal structure can be constructed, it is considered suitable.
Through some experimentation, it is thought that metals like titanium, when found in abundant enough quantities, works well for this purpose. As the allergy to iron is relatively pervasive throughout Eisa, materials containing it is not frequently utilized. Not only would it have a detrimental effect upon anyone unfortunate enough to go through it, but it was entirely possible that the portal itself would be nonfunctional due to its own reaction to the material.
In the best case scenario, once the structure has been built to contain the portal, and a mechanism to switch between the portals contained within the structure constructed, a team of four portalsmyths work together to connect the wild portal to the structure. In the absence of more than one portalsmyth proper, such that occurs frequently within our modern age, anyone with mage talent can serve to fille the other three roles within the ritual. The material makes the difference in how the ritual is performed at this point, as each material needs different techniques to attach it. Stone archways require each stone making up the arch to be connected to the wild portal individually, with the bulk of the connections coming through the keystone that holds the arch as a whole.
Titanium-framed portals are a different matter, as it is a more fluid process. It is seen by some as an easier process that is more able to be done by a single portalsmyth, but this has been known to put enough strain on that single portalsmyth that they are unable to do anything else for the better part of the day, and there is still one step remaining in the procedure. 
Due to the shortage in portalsmyths in the area, the Terran side of the Stiwen portal network is a series of single portals for this reason, as there was only one portalsmyth, one minor portal technician, and a mage to reinitiate the network after it had fallen off the network at the time of Calarael's abduction. It is unknown whether having the Royal ripped from the Court the way that had been done unleashed enough instability the demesne was unable to maintain the agreement between the Royals and the portals they had agreed to work with, or whether it was done on purpose to prevent anyone who might have been able to go after her from following.
In all other instances of portals, once the wild portal is bound into the frame, if the structure is meant to be a networked portal structure, they have to be linked into the interface, where the locations can be accessed by anyone wishing to travel. Each structure is limited to five locations, because any further wild portals contained within one structure, especially the stone structures that are most common amongst the older demesnes, will start to break down the structure faster than expected. The risk of being caught between locations, and finding oneself trapped either in the Nothing or in a location they didn't intend upon arriving at grows with the number of wild portals bound into a single structure increases.
For that reason, and for the possibility of needing to add emergency locations to a particular interface (frequently referred to as a 'dial'), most demesnes seldomly have more than three wild portals woven into a particular structure. As one of these portals is most likely to lead to the Terran side of any given Eisan demesne, this means there is the likelihood that each Court is only connected to two other locations, meaning that it might take time for a person to make their way toward their eventual destination.
As there are no better options at the moment for transport, most people accept this, though there might be some complaints about the round-about route they are required to take in order to reach their intended destination.