> Is it possible to leave a list open to internal users only????

Click on this URL for more information:
http://www.lsoft.com/manuals/1.8e/owner/owner.html#_Toc9154371

This is the appendix for the List Keywords.

If you're still doing this under 1.8c, use this URL:

http://www.lsoft.com/manuals/1.8c/owner/appendb.html#Local