It was intended to be interesting. :-)
Likely the Dingir League at least has a trade representative office present that assists traders from the Dingir League with a variety of issues from trade disputes to regulations to arranging introductions with locals. It would make perfect sense that there would be additional "personnel" that work out of the office as well.
The Terrans also have a trade representative office (and a Temple of the Faith no doubt), but you are right, the J-3 gap that helped to protect Terra during the Collapse also restricts movement of merchants in and out of the Republic.
Likely the Dingir League at least has a trade representative office present that assists traders from the Dingir League with a variety of issues from trade disputes to regulations to arranging introductions with locals. It would make perfect sense that there would be additional "personnel" that work out of the office as well.
The Terrans also have a trade representative office (and a Temple of the Faith no doubt), but you are right, the J-3 gap that helped to protect Terra during the Collapse also restricts movement of merchants in and out of the Republic.