My suggestion would be to modify the selection list and build an array in
memory of the items that were "pulled". THen when the user changes columns,
rebuild the selection list "on the fly". You would need to use this function
to do this:

Private Sub Workbook_SheetSelectionChange(ByVal Sh As Object, ByVal Target
As Range)

End Sub
which you would place in the "ThisWorkbook" area in VBA. You would need to
record what column you are in when you load the spreadsheet so you can then
be able to identify when the column changes. This doesn't sound too
difficult to me, but if you need help doing this let me know.

You would need to create a public variable to record the column using the
Private Sub Workbook_Activate()

End Sub
sub that would be placed in the same area. Then in the Change sub
(displayed above), have code that would change the data in the selection
range. Good luck!