Salut Alex, Salut le Forum !
En passant par VBA ?
Sub Concatener()
Dim w As Long, x As Long, y As Long, z As Long
Dim Txt As String, Personne As String
x = Range("A" & Rows.Count).End(xlUp).Row
For y = 2 To x
If Cells(y, 3) = "" Then
Personne = Cells(y, 1)
Txt = Cells(y, 2)
For z = y + 1 To x
If Cells(z, 1) = Personne And Cells(z, 3) = "" Then
Txt = Txt & "&" & Cells(z, 2)
Cells(z, 3) = "x"
End If
Next
w = Range("D" & Rows.Count).End(xlUp).Row + 1
Cells(w, 4) = Personne
Cells(w, 5) = Txt
End If
Next
Columns(3).ClearContents
End Sub
Restant à dispo