Compare Two Columns Between Two Worksheets, keep duplicates, delete others, copy new

I've looked at many treads on this topic, but can't seem to get exactly what I need to happen. Here's the process I'm looking to perform:
-new data are imported to "import" worksheet from separate excel workbook
-old data are located in "master" worksheet
-Compare columns "E" & "J" for each row in both worksheets
-if match, keep row in "master" worksheet
-delete no-match rows in "master" worksheet
-copy remaining new data rows from "import" worksheet into "master" worksheet


This is what I've tried to start with. If there's a way to skip the "import" worksheet and just do the analysis during the import process from the separate excel workbook, that would be even better. Thanks for any assistance you can provide.
Scott

Sub test() 
    Dim a, i As Long, ii As Integer, z As String 
    Dim n As Long, AB(), F_P(), x As Long, e 
    a = Worksheets("Import").Range("a1").CurrentRegion.Resize(, 19).Value 
    Redim F_P(1 To UBound(a, 1), 1 To 19) 
    With CreateObject("Scripting.Dictionary") 
        .CompareMode = vbTextCompare 
        For i = 1 To UBound(a, 1) 
            z = a(i, 5) & ";" & a(i, 10) 
            If Not .exists(z) Then 
                n = n + 1 
                For ii = 1 To 19 
                     
                    F_P(n, ii) = a(i, ii) 
                     
                Next 
                .Add z, n 
            End If 
        Next 
        a = Worksheets("Master").Range("a1").CurrentRegion.Resize(, 19).Value 
        For i = 1 To UBound(a, 1) 
            z = a(i, 5) & ";" & a(i, 10) 
            If .exists(z) Then 
                n = n + 1 
            Else 
                 
                For ii = 1 To 19 
                     
                    a.Rows(a).Resize(, 19).Cut Sheets("Master").Rows(k) 
                     
                Next 
                .Add z, n 
                 
            End If 
        Next 
        Worksheets("Master").Range("a1").CurrentRegion.Resize(, 19).Value = a 
        If .Count > 0 Then 
            Redim a(1 To .Count, 1 To 19): n = 0 
            For Each e In .keys 
                x = .Item(e): n = n + 1 
                For ii = 1 To 19 
                     
                    a(n, ii) = F_P(x, ii) 
                     
                Next 
            Next 
            Worksheets("Master").Range("a" & Rows.Count).End(xlUp)(2) _ 
            .Resize(n, 19).Value = a 
        End If 
    End With 
End Sub