1 campaign, multiple identities

I have a high volume of prospects and I need to launch them with the same wording + campaign structure. As things are, I need to create 1 campaign per identity. this takes longer to set up. And in the scenario where I need to make a change, I need to make a change to each campaign. = pain. Ideally, I would have 1 campaign and add as many identities to that campaign. Not as good but still better: still have 1 campaign per ID but have a master campaign that I can duplicate. If I make a change to the master campaign, it makes changes to all of the campaigns.