New Units... out of customizable folders

Hey guys, I wanted to import some more units from hellenic total war to my personal mod of the original game. However, I've used up all 10 customizable folders. I tried to re use the old folders that i had to change when adding my new factions (peasant, plates, mshelm, etc.) by putting the units from hellenic in them and changing the bif names as well as the unit_prod file location column, but my game still crashed. Can anybody help me to be able to add some more units from HTW to my game beyond using the 10 customizable folders and not replacing the original game's units' folders?