Run Goalseek Macro On Filtered Data

I have written a macro that uses the goalseek function over an entire column. It works and is a happy macro. the only problem with it that I see is that it currently cannot work through a filtered list. Say, for instance, you have a column(a) that adds column(b) + column(c). Lets say that there's 10,000 rows and of those, 8,000 have a value over 10. You apply a filter and view the other 2,000 rows with values less than 10. If you run the macro in its current state you'd apply the results to all 10,000 lines - but I wish to do it only over the remaining 2,000.

I'm certain that some variation of .SpecialCells(xlCellTypeVisible) will be used but I cannot determine where. Here's my code.

Sub TryMe()
'set the goalseek area
answer = MsgBox("Please note that this macro only works on consecutive cells." & _
vbNewLine & "It will NOT work on a filtered list." & vbNewLine & vbNewLine & _
"Continue?", vbYesNo)
If answer = vbNo Then
Exit Sub
End If

restart:
With Application
On Error Resume Next
Application.DisplayAlerts = False ..............