Is is possible to create a new collection and use a field such a boolean to determine whether that row of data added to the collection is shown on a connected repeater element on a page?
Perhaps one element on the repeater could be hidden although connected to the collection so that a particular code snippet could be added to the page code?
Yes. Once you’ve added the boolean column to your collection, just select your dataset, click Settings, then Add Filter. It should be fairly intuitive from there.
If you were to use code, you’d not need any hidden elements inside the repeater because you’d have access to the entire row of data already. But if you’re using datasets, it’s probably easier for you to set this up in the editor GUI.