I've not read the source book, but it would make sense to me that, in addition to a team in each capital city, that there are IST offices in major cities in most nations that aren't capitals. Whether these are any more than a small staff and hero or two would depend on things like populace, international impact, and history. So you might have an IST office in Dallas, renting space in the Downtown area (or perhaps in the more centrally located business park area of Las Colinas, so that one office could cover Dallas and Ft. Worth), but it might be like the consulates that keep offices in Dallas, a small presence.
Ebony the Black Dragon
http://ebony14.livejournal.com
"Good night, and may the Good Lord take a Viking to you."
Ebony the Black Dragon
http://ebony14.livejournal.com
"Good night, and may the Good Lord take a Viking to you."