How to transpose certain cells to column

Here is a (crude) way of doing it in Power Query.  I am sure this can be optimized.

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("nZDBTsJAEIbfpWdiIorCrcQAESmYGg+GcJg0Y13dnSHTauDtndl6M1TZ0/dnd+fL7L/dZpfjm1E2yO7X8015tyk0LmZlMV2/aFp+Nq0jDe8x5OFYcdgDHS+UNkQtCoHPdoN+0VOLX2iiJoZ00ZLR1mHMHb2y6PSPYXb4p2Hq8aAARbKjAPlQBMW5DpSg347dQtcsUL/jdjIe6uGKa9ddzwWowljGW1Qo/mj0tKN0VLNSjLnvHpy5xwJZagt1DImWwlWxVEWioWSrQ5j65odX16OJHj4KBxYbe36wLiFgY2Ua+9s8YViBmMAr0uYd2FOvSJpfM3oFKfJ9d/Xr/7tv", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Partner ID" = _t, #"Partner Name" = _t, Country = _t, Name = _t, #"Email Address" = _t, #"Internal/External" = _t]),
    #"Added Custom" = Table.AddColumn(Source, "Custom", (k)=> Table.SelectRows(Source, each [Partner ID]=k[Partner ID] and [#"Internal/External"]="Internal")),
    #"Added Custom1" = Table.AddColumn(#"Added Custom", "Internal", each Table.SelectColumns([Custom],{"Name","Email Address"})),
    #"Added Custom2" = Table.AddColumn(#"Added Custom1", "Custom.1", each Table.ToList([Internal],Combiner.CombineTextByDelimiter(","))),
    #"Extracted Values" = Table.TransformColumns(#"Added Custom2", {"Custom.1", each Text.Combine(List.Transform(_, Text.From), ","), type text}),
    #"Filtered Rows" = Table.SelectRows(#"Extracted Values", each ([#"Internal/External"] = "External")),
    #"Split Column by Delimiter" = Table.SplitColumn(#"Filtered Rows", "Custom.1", Splitter.SplitTextByDelimiter(",", QuoteStyle.Csv), {"Custom.1.1", "Custom.1.2", "Custom.1.3", "Custom.1.4", "Custom.1.5", "Custom.1.6"}),
    #"Removed Other Columns" = Table.SelectColumns(#"Split Column by Delimiter",{"Partner ID", "Partner Name", "Country", "Name", "Email Address", "Internal/External", "Custom.1.1", "Custom.1.2", "Custom.1.3", "Custom.1.4", "Custom.1.5", "Custom.1.6"})
in
    #"Removed Other Columns"