How to create third dependent dropdown list?

I hope someone can help me.
From the attached table, I've created dropdown list for "Barangay" & "Town_City".
The other column will auto fill upon selection of Barangay & Town_City.
But, I really want to create for that is.....
1) Three Dropdwon list in three columns (Barangay, Town_City and Province) with dependent validation lists.
- If I select one Barangay, Town_City will only list related lists of selected Barangay. Also Province list will show relate province of selected Town_City.
You can see my excel file. I created two dropdown lists. But I've problem to create third dropdown list for Province.
2) I want dropdown list with single value list. What I mean is I don't want to list "multiple values" (eg. two or three same name of Barangay/Town_City are listed in my excle file).
You can see there are many same name in different columnes. I don't know how to control in list item for single value.
3) The last thing is if I delete or reselect "Barangay", I want automatically delete other selected value from "Town_City" and "Province".

The attached is my excel file.

DataTemplate.xlsx

Maybe this will do it. There is a sample file for download.

http://www.contextures.com/xlDataVal15.html

I don't fully see what the exact problem is. Can you give a couple of specific examples of what you don't want to happen and/or what works good?

Sorry but I do not have a solution for this. Maybe somebody else will have the solution.

the DV formula in B2 should be:

=OFFSET(Barangaystart, MATCH($A2, Barangay, 0)-1,1,COUNTIF(Barangay,$A2),)

that's really a subject for another thread, or a search of the forum, as I'm sure its been discussed several times

If you want a list with no dupes, that list has to exist. I would copy the first two columns (Barangay and Town) list to another location using Advanced Fitler > Unique Values to eliminate the dupes, and name that new Barangay column BarangayShortList, now the same technique as above works.

=OFFSET(BarangayShortList, MATCH($A2, BarangayShortList, 0)-1,1,COUNTIF(BarangayShortList,$A2),)

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