no you cant
sorry

There is one way to make them believe it's just a normal map tho. You can use Addon Share mod, this will allow your friends to join without downloading all the mods/maps manually. Or you can make a mod collection with several mods and hide the haunted map there, i doubt your friends will go through the whole list, usually people use ''subscribe to all'' option. Of course there is a high possibility of them noticing during the loading screen, but it depends on how you distract them. Well, that may sound too complicated, but i have no better ideas