Need Help on Ship Limit Construction

I'm working on a mod for my son, and I've added dreadnoughts for all of the factions. I'd like for them to be limited to one dreadnought built at a time, the same way as Titans. My first try was to add the titan's research prerequisites to the dreadnoughts. This of course did not work, could still build as many as I wanted once the tech was researched. I have the dreadnoughts listed as a Capital Ship. In the titans entity files, their stat count type is listed as "Titan". So far this is what I'm thinking; Rename the dreadnought entity files, taking out capital ship and replacing it with dreadnought. Creating their own factory for the dreadnoughts to be built, and having their "stat count type" listed as "Dreadnought". A new research subject which puts a construction cap onto the dreadnoughts. The problem is, I haven't been able to find where in the game that they determine the "stat count type" at. I figured it would be in the gameplay constants entity file, but did not find anything, or anywhere else for that matter and now I'm at a loss. Any help would be most appreciated.