Hello Herbert,
This is untested but I believe it should do what you want. This will first open the workbook in columns "A:B" as the main workbook. This will remain open until all the associated workbooks in columns "C" have been opened and closed.
Try this macro and let me know the results. It probably will need a little adjusting.
Sub UpdateWorkbookLinks()
Dim Cell As Range
Dim File As Variant
Dim MainWkb As Workbook
Dim Path As String
Dim Rng As Range
Dim RngEnd As Range
Dim SubRng As Range
Dim Wkb As Workbook
Dim Wks As Worksheet
Set Wks = Worksheets("Group iAL")
Set Rng = Wks.Range("B6:E6")
Set RngEnd = Wks.Cells(Rows.Count, "D").End(xlUp)
If RngEnd.Row < Rng.Row Then Exit Sub
Set Rng = Rng.Resize(RowSize:=RngEnd.Row - Rng.Row + 1)
Set Cell = Rng.Columns(1).Cells.Find("*", , xlValues, xlWhole, xlByRows, xlNext, False, False, False)
If Cell Is Nothing Then Exit Sub
Set FirstCell = Cell
Do
Path = Cell.Offset(0, 1).Hyperlinks(1).Address
Path = IIf(Right(Path, 1) <> "\", Path & "\", Path)
Set MainWkb = Workbooks.Open(Filename:=Path & Cell.Text, UpdateLinks:=True)
Set SubRng = Intersect(Cell.CurrentRegion, Rng).Columns(3)
For Each File In SubRng.Cells
Path = File.Offset(1, 0).Hyperlinks(1).Address
Path = IIf(Right(Path, 1) <> "\", Path & "\", Path)
Set Wkb = Workbooks.Open(Filename:=Path & File.Text, ReadOnly:=True)
Wkb.Close SaveChanges:=False
Next File
MainWkb.Close SaveChanges:=True
Set Cell = Rng.Columns(1).Cells.FindNext(Cell)
If Cell Is Nothing Then Exit Do
If Cell.Address = FirstCell.Address Then Exit Do
Loop
End Sub