How can I get teams to only sign players from certain areas?
 

I'm trying to build an online league where teams can only sign players within a certain distance of their major and minor league cities. Are there any existing mods that do this, and if not, does anyone have a suggestion for how to go about it?

You would need a copy of the old world.csv file and spreadsheet skills. The new world.dat file will not work very well. It could still be done but nowhere near as easily.