Custom column for counting processes with different IDs.

let
    fx_seq = (tbl) => 
        [
            val = List.Buffer(tbl[Value]),
            seq_list = List.Zip({val, List.Skip(val, 1), List.Skip(val, 2)}), 
            positions = List.Buffer(List.PositionOf(seq_list, {40, 50, 60}, Occurrence.All)), 
            tbl_to_join = #table(
                {"desired result", "i"},
                List.TransformMany(
                    List.Positions(positions),
                    (x) => List.Numbers(positions{x}, 3),
                    (x, y) => {x + 1, y}
                )
            ), 
            result = Table.Join(Table.AddIndexColumn(tbl, "idx"), "idx", tbl_to_join, "i", JoinKind.LeftOuter), 
            sort = Table.RemoveColumns(Table.Sort(result, "idx"), {"idx", "i"})
        ][sort],
    Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content], 
    group = Table.Group(Source, "ID", {"x", fx_seq}), 
    z = Table.Combine(group[x])
in
    z