Autofilter on multiple columns simultaneously (follow up of 21934613)

This is a follow up on a really cool excel technique from
http://www.experts-exchange.com/Applications/MS_Office/Excel/Q_21934613.html

I have an excel parts database with 50000 records.
I defined column names of SKU, Desc, MfgSKU.  (I will eventually add 15 more columns)
           
textboxes tbSKU and tbDesc are in row 1 of the corresponding column.

The following worksheet vba establishes tbSKU AND tbDesk as "instant zoom filters".  

As I keystroke the text "cirrus hood" into tbDesc. The 50000 rows shown instantly "zoom in" to show the 100 records containing "cirrus hood". (Even with 50000 records it appears to be instantaneous! Each keystroke lowers the number of rows from 50000 to 40000 etc until only 100 records show.  )

Next I keystroke 123 into tbSKU.  Although tbDesc still displays "cirrus hood", that filter is dropped, so we jump to 50000 records then zoom in to the 15000 records containining 123.  

I want to change the vba so that the "Cirrus hood" filter remains in place. Thus every textbox's value will be combined so the filter shows filter 1 AND filter 2 AND future filters 3 to 15.

Hope someone can help me.

Bob
P.S. If anyone is interested, I will eventually put the column names into an array, then rewritie the routine to use that array wherever possible. But the 500 points doesn't require any use of this idea.
something like
   if myColumnNames is nothing then set myColumnNames = array("desc","sku", etc).  

------ here is my current code ------------

Private Sub tbDesc_Change()
    Call generic_change(tbDesc)
End Sub

Private Sub tbSKU_Change()
    Call generic_change(tbSKU)
End Sub

Sub generic_change(tbChanged)
    Dim colChanged As Range
    Set colChanged = Range(Mid(tbChanged.Name, 3))
    colChanged.AutoFilter Field:=1, Criteria1:="*" & tbChanged.Value & "*", VisibleDropDown:=False

    If UCase(tbChanged.Value) = "" Then
        ActiveSheet.AutoFilterMode = False
    End If
End Sub


Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    Set genericColumns = Union([desc], [sku])  
   
    If Intersect(genericColumns.Rows(1), Target) Is Nothing Then Exit Sub
   
    If Target.Count > 1 Then
        MsgBox "Proceed at your own risk, your selection includes special search cells " _
            & Intersect(genericColumns.Rows(1), Target).Address
        Exit Sub
    End If
    ' if user uses arrow keys to enter cell, activated the text box instead of the cell.
    If Target.Column = [desc].Column Then Me.tbDesc.Activate
    If Target.Column = [sku].Column Then Me.tbSKU.Activate
End Sub