Sub TestInsert()
Dim Target As Range, C As Range, Lr As Long
Set Target = Cells(ActiveCell.Row, ActiveCell.Column + ActiveCell.MergeArea.Columns.Count)
For Each C In ActiveCell.MergeArea.Columns
Lr = WorksheetFunction.Max(Lr, ActiveSheet.Cells(ActiveSheet.Rows.Count, C.Column).End(xlUp).Row)
Next
Range(ActiveCell.Address).Resize(1 + Lr - ActiveCell.Row, ActiveCell.MergeArea.Columns.Count).Copy
Target.Insert xlShiftToRight
End Sub