How do I use Multiple Joins and Conditions using LINQ?

[Christhemist]

I have three DataTables and Three conditions in which I need to combine into one "Combined" DataTable:

Input:

AddressList
First
Last
Address
City
State
Zip
Offercode

Matrix1
Code
Offer1

Matrix2
Code2
Offer2

Output: (CombinedDataTable)
First
Last
Address
City
State
Zip
Offercode
Offer1
Offer2

My syntax for the these are not working in the "On" and "Concat" portions:

Dim both = From row1 In AddressListDatatable.AsEnumerable()
                       Join row2 In Matrix1Datatable.AsEnumerable()
                       Join row3 In Matrix2Datatable.AsEnumerable()
                   On row1.Field(Of String)("Offercode") Equals row2.Field(Of String)("Code") And
                   On row1.Field(Of String)("Offercode") Equals row3.Field(Of String)("Code2")
                       Select addressListColumnNames.Select(Function(alcn) row1(alcn)).Concat(matrixColumnNames.Select(Function(mcn) 
                       row2(mcn)))  row1(alcn)).Concat(matrix2ColumnNames.Select(Function(mcn2) row3(mcn2)))

For Each result In both
                CombinedDataTable.Rows.Add(result.ToArray())
            Next