power query code that count duplicates on multicolumn data

[theo]

Need help on correcting this code to count duplicates this duplicate of current row against all rows.  Any help is appreciated

Table.AddColumn(Source, "Add",
each List.Count(
Table.SelectRows(
    Source,
    (C) => List.Intersect(Table.ToList(Source),C(Table.ToList(Source)))=5
)[Column1]
))

[v-chuncz-msft]

@theo 

You may try using Table.Group.