I think you can handle the change but not scroll.
For example you have 2 listboxes with Customer IDs & Customer Names. The below code will select the item based on selected item of other listbox(I don't have VB 6 now :( )
Private Sub listboxID_Click()
listboxName.ListIndex = listboxID.ListIndex
End Sub
Private Sub listboxName_Click()
listboxID.ListIndex = listboxName.ListIndex
End Sub