Check/uncheck one item will also check/uncheck subitems

Hi, i need help on Excel Formula, trying to create input formula as follow.

① Ideally, if cell A1 is checked, I want C1:C4 to be automatically checked accordingly.
② But also to be able to manually check or remove the selected checkmarks from C1:C4.
③ Furthermore, I would like to make it so that unchecking A1 will automatically uncheck all of C1:C4.
④ And, C1:C4 be checked again if A1 is checked.

Is this possible using only Excel Formula, Conditioning, and probably Data Validation? (Just not Macro)

Thank you tons!

スクリーンショット 2022-06-03 0.31.38.png

Welcome to the Forum 3po! !

What do you want to happen if you check A, all the other boxes are checked, then you manually uncheck one? Does A stay checked?

If you need to have the checkmarks work in both directions it is going to require a macro.

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This is a macro solution. I see no other way to do this. To do it with formulas means that C1:C4 have to have formulas, but you want to be able to update them manually so they cannot have formulas.