Create unique items in valiadtion list

Hello everyone
I have a validation list of three items (A,B,C)
these values are in column A ..
In E4 I have validation list of the three values (A,B,C)
The required in F4 to create validation list of unique items for specific item
As an example if I select A in cell E4 , i expect to have a list of these values(20,5,9,19) only
Hope it is clear

On the Worksheet Module -

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On a regular code module -

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See the file attached for reference.

After seeing Berlan's code, I just realized I missed out on the "Unique" Part..

Sorry!

another way of doing it:

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Thanks a lot everyone for these great solutions
@NeedForExcel it is ok but for it brings all the values .. I refer in my request to unique values
@bulina2k very good solution but its problem it depends on columns inside the sheet and creating named ranges ..
@ berlan yout code is perfect for me frankly ..

Is it possible to create a dynamic list (unique results) by formulas ? just for curious
Thank you very much for you great help

@Mr Berlan
How to deal with the following attachment
I need to create a nother validation list based on F4 in cell G4
Sorry for bothering you again

You are awesome ..Thank you very much for this wonderful solution