Most of the minimods are built using downloadable pk3 files which get distributed to your players and run for all maps.
One possible way around this would be to put the character skins within the map pk3 so they would be executed when that map runs. Then the next map would have different character files which would then be executed, and so on. However this could get quite messy and might not reset to the normal default character skins properly. Also you will need to rename these files with unique new names so they load after the default skins, and are not confused with the original map names.
It is possible but tedious and it could mess up players ET installations if you dont do it properly.
You might be able to do this better with lua or enhmod or some other hook.
- SadNesS likes this