Calling Functions in Detail Controller from List Controller

I’m sure I read something about this previously but now I’m looking for it can’t find anything.

I have an application based on the standard side-menu template. I’ve added to the PlayList controller, functions to display a modal form for updating the play list data. This works fine.

On the PlayLists list controller, I’ve added an action sheet, one of whose items attempts to call the modify function from the PlayList controller to edit the item that was touched. This doesn’t work and throws an “undefined” exception. I presume that this is because the function is only defined when the application transitions to the detail route.

Is there a recommended way to define functions on a detailed object and then call these functions on a specific item from a list view?