Hide Columns Loop Fails Over Multiple Sheets

Hi all,

I hope I get this right as it's my first post. I am trying to loop through a list of sheets. In each sheet I want a range of cells to be assesed and then the columns hidden based on the cell value. I can get this macro to work as long it is for one sheet. As soon as I extend the loop to look at more than one sheet, I get an error message. It's the first time I have used the Union function, something I am not used to. Any help would be most welcome, I've been looking at this for ages!

Sub HideColumns()
    Dim ColumnsToHide As Range
    Dim SelectedCells As Range
    Dim Cell As Object
    Dim Item As Range
    Dim TeamTab As Range
    Set TeamTab = Sheets("Options").Range("D9:D10")   '"TeamTabs"
    'Set ColumnsToHide = Range("P4:AA4")
    
    For Each Item In TeamTab
        'On Error Resume Next
        With Sheets(Item.Value).Select
                Sheets(Item.Value).Range("P4:AA4").EntireColumn.Hidden = False    'ColumnsToHide.
                For Each Cell In Sheets(Item.Value).Range("P4:AA4")
                        If Cell.Value = 1 Then
                            If SelectedCells Is Nothing Then
                                Set SelectedCells = Range(Cell.Address)
                                Else: Set SelectedCells = Union(SelectedCells, Range(Cell.Address))
                            End If
                        End If
                Next
                If SelectedCells Is Nothing Then
                    Sheets(Item.Value).Range("P4:AA4").EntireColumn.Hidden = False
                    Else: SelectedCells.EntireColumn.Hidden = True
                End If
        End With
    Next Item
End Sub