Excel VBA: CONCATENATE + IF/LOOKUP

Hi there,

not having found a suitable set of excel formulas solving my issue ad-hoc, I went ahead looking into Macros. This is what I want to do:

- CONCATENATE a set of fields in one column
- IF the field in the colum left of my text-field matches a certain criteria

Basically replicating the checking functionality of SUMIF, just with concatenate.

I have found relevant VBA-snippets that I have tried to combine. However, I am lacking the criteria-checking functionality. Here is what I got:

Function JoinIF(source As Range, checkrange As Range, criterion As String, Optional delimiter As String) As String
    Dim sResult As String
    Dim oCell As Range
    Dim cCell As Range

    For Each oCell In source.Cells
        If Len(oCell.Value) > 0 Then
            If cCell.Value = criterion Then
                   sResult = sResult + CStr(oCell.Value) + delimiter
            End If
        End If
     Next

    Join = sResult
End Function

This naturally does't work, as I am not checking the correct cCell value (second IF-Check).

Hence my question: How can I get the correct cCell to check against in the game here?

Thank you for your help!

Best regards,
Andreas