Mike, objects do have a visibility property . . . 
You can make objects visible or in invisble with:
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;;;
;;;
;;; BLANK.LSP Version 1.0
;;;
;;; Copyright (C) 1995 by Autodesk, Inc.
;;;
;;; Permission to use, copy, modify, and distribute this software and its
;;; documentation for any purpose and without fee is hereby granted.
;;;
;;; THIS SOFTWARE IS PROVIDED "AS IS" WITHOUT EXPRESS OR IMPLIED WARRANTY.
;;; ALL IMPLIED WARRANTIES OF FITNESS FOR ANY PARTICULAR PURPOSE AND OF
;;; MERCHANTABILITY ARE HEREBY DISCLAIMED.
;;;
;;;
;;; BLANK, UNBLANK, and UNBLANKALL
;;;
;;; This module provides functions to manipulate the visibility field of
;;; AutoCAD objects. BLANK will make a selection set of objects invisible.
;;; UNBLANK will make a specified object (given its handle) visible.
;;; UNBLANKALL will make all blanked entities visible.
;;;
;;;
