front end - Programmatically selecting non adjacent Cells

One can of course Ctrl + MouseClick to select 1st and 3rd cell.

But how to select non adjacent Cells programmatically?

I was looking for neat examples here or in the documentation but I was not able to find suitable Option / function / FrontEndToken.

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The method I've prepared is good enough for many cases so I'm posting it as an answer but I will gladly accept other if it deals with following issues:

• Using my method, to expand selection one need to rescan all already selected. Not really efficient.

and a minor issues

• This is ugly big amout of code for such simple operation.


• I was not able to manipulate CellTags with CurrentValue. Not quite sure why.