I think that what I would do, is to separate the map into multiple layout, and have all of them use the same general event sheet.
Just like zelda games you have the main field , then a town, the montain, the forest, the river, the dungeons, etc; all on their individual layouts. And if each area uses too many events, you could have those in their individual event sheets and include them when you load an area. Or have the area events in groups and enable/disable those when necessary, so they don't eat up processing time just waiting for their turn to play
I don't understand why you think you need to duplicate anything though =O
i would have a passive layout to store all the "waiting" objetcs, like enemies ans such. And create them on demand, like with triggers something.