Importing files in custom campaign

When I create a custom campaign and I have in it several maps that all use the same imported models and skins, do I have to import everything in each map or can I import everything once and for all in the custom campaign file ?

Course u got import them to that maps

just remember a campaign is just a line that holds maps together

Well I just thought importing all the files in each map would increase the size of the campaign a lot. But I just found out there is an importer in the campaign editor that allows you to import all the files you need for the whole campaign once and for all, so I got no problem anymore, thanx.