I must be missing something since the Mad Scientists have written ominous code. Is it possible to make a kind of backdrop? “Ocean is a kind of backdrop. Big Ocean is an Ocean. Shallow Water is an Ocean.” Use “Big Ocean” where it remains, and then “Shallow Water” in individual rooms where the tide goes out so you can say “Now Shallow Water is off-stage” when necessary. Same backdrop, but divided into kinds? If you replace it you’d just have to declare each room “Now Shallow Water is in Under the Pier; Now Shallow Water is in Coral Reef”…
Not tested…I’m likely missing something.