Extract unique data and concatenate

Hi guys

I have these Sheets1-3 with different item name ,and sheet4 = "ALL ITEM"

We populate the data(daily/weekly) in Sheet 1-2-3, there are the same Item codes with different Item Description. Sometimes with random input--not sorted.

1 . In sheet 4 - ALL ITEM, we extract(manually) from Sheet1-2-3 the single/unique item code with its item description(s) concatenated in a single cell, as we input new data at the end of the day or week in Sheets 1-2-3..
is there a way or possibility with an excel formula to automatically update Sheet 4-(extract unique code+concatenate all its item desc in single cell)
- And what if the source data from another workbook?
Need help.


With the contribution of the genius in this forum, I used the UDF suggested before to concatenate a single or huge data in a colum.

=Conc(C2:C4,",") - separated by comma.
--
Option Explicit

Function Conc(rng As Range, Optional Separator As String = "")
Dim Cell As Range

For Each Cell In rng
If Cell <> "" Then
Conc = Conc & Separator & Cell
End If
Next
If Separator <> "" Then
Conc = Right(Conc, Len(Conc) - Len(Separator))
End If
End Function
--

I hope my explanation makes sense, I have attached the sample data.
Cheers, Many thanks dear experts!

D