need help - Power query or M code solution needed

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Yep.

let
    Source = 
    #table(
        {"Column1", "Column2", "Column3", "Column4", "Column5", "Column6"},
        {
            {"Monitor", "Usergroup", "Monitor_group", "Contact", "", ""},
            {"Monitor1", "Usergroup1", "Monitor_group1", "Contact1", "", ""},
            {"Monitor2", "Usergroup2", "Monitor_group2", "Contact2", "", ""},
            {"","","","","",""},
            {"Monitor", "Poller", "Contact", "Monitor_group", "Usergroup", ""},
            {"Monitor3", "Poller3", "Contact3", "Monitor_group3", "Usergroup3", ""},
            {"Monitor4", "Poller4", "Contact4", "Monitor_group4", "Usergroup4", ""},
            {"","","","","",""},
            {"Monitor", "Contact", "Usergroup", "Poller", "Monitor_group", "Portnumber"},
            {"Monitor5", "Contact5", "Usergroup5", "Poller4", "Monitor_group5", "Port5"},
            {"Monitor6", "Contact6", "Usergroup6", "Poller5", "Monitor_group6", "Port6"}
        }
    ),
    add_local_group_column = 
    Table.AddColumn(
        Source, 
        "placeholder", 
        each if [Column1] = "" then null else "G", 
        type text
    ),
    local_group = 
    Table.Group(
        add_local_group_column, 
        {"placeholder"}, 
        {
            {"AllRows", each Table.RemoveColumns(_, {"placeholder"}), type table}
        }, 
        GroupKind.Local
    ),
    remove_null_rows = 
    Table.SelectRows(
        local_group, 
        each ([placeholder] = "G")
    ),
    remove_nested_blanks = 
    Table.TransformColumns(
        remove_null_rows, 
        {
            {"AllRows", each Table.Transpose(Table.SelectRows(Table.Transpose(_), each ([Column1] <> "")))}
        }
    ),
    promote_nested_headers = 
    Table.TransformColumns(
        remove_nested_blanks, 
        {
            {"AllRows", each Table.PromoteHeaders(_, [PromoteAllScalars = true])}
        }
    ),
    nested_column_names = 
    Table.AddColumn(
        promote_nested_headers, 
        "columnNames", 
        each Table.ColumnNames([AllRows]), 
        type list
    ),
    distinct_column_names = 
    List.Distinct(
        List.Combine(nested_column_names[columnNames])
    ),
    remove_columns = 
    Table.RemoveColumns(
        nested_column_names,
        {"placeholder", "columnNames"}
    ),
    expand_desired = 
    Table.ExpandTableColumn(
        remove_columns, 
        "AllRows", 
        distinct_column_names
    )
in
    expand_desired