How to multi-select scene hierarchy objects in code

Hello, I've been trying and failed to use the Selection class to multi-select some objects in the scene hierarchy -similar to how you would by holding down Ctrl and clicking on all the objects you want selected. Does anyone have suggestions or ideas to achieve something similar? I have a list and a serialized bool property in my monobehaviour. When i toggle the bool, the items in the list -which are also objects in the scene, should all be selected.

Thank you.