If you make no changes to the units loadouts you can simply apply the faction config at the mission level by pasting it into description.ext. This is the method mentioned here :Įditing an existing addon: select the faction and change the side/flag but leave the name and classname the same.
Then I changed the faction name in the description.ext. I made a faction by merely changing the side of an existing one from blufor to opfor and exporting the full faction cfg to description.ext.