Dans ce cas, avec une fonction :
Function Concatener_Plage(plage As Range) As String
Dim cel As Range
Concatener_Plage = ""
For Each cel In plage
If cel <> "" Then
Concatener_Plage = Concatener_Plage & Cells(4, cel.Column).Value & "-"
End If
Next
Concatener_Plage = Left(Concatener_Plage, Len(Concatener_Plage) - 1)
End Function