Redirect Cell Events to another Cell

[Adam Rule]

I am experimenting with a notebook extension that enables a 2-panel view. The left panel is for the high level overview cells, and the right panel for implementation details (see the link for an example gif). You can think of it as a new way of 'hiding' cells with the hidden cells being moved to a separate panel to the right rather than collapsed inline. 

I am wondering if there is an intelligent way to implement such a 2-panel view that does not hurt the integrity of the notebook (which assumes a linear collection of cells in the notebook div) or requiring extra event passing.

My current approach is to hide cells in the notebook and create a duplicate of the hidden cell in a new sidebar div on the same level as the notebook. However, now I think I need to redirect events performed in that duplicate cell (e.g., cell selection, execution) to the original hidden cell to get the notebook to behave as I want. This seems like a lot of manual redirecting.

Can you think of a better way to either visually move the original "hidden" cell, or to link the hidden and duplicate cell?