We put it together and later on it could be worth testing as an isolated campaign with just a specific theme (grouped custom intent KWs) but you don't want to limit placements, or age too much as that may cause ad not to serve.
Hello there! 1 Audience in 1 campaign for easier optimization and scaling. Adding multiple audiences into 1 ad group or campaign is called "spaghetti testing" and it's not a best practice due to not knowing what audience actually worked.