Using your suggestion as a guide I looked System Access Points and pulled up the Help Menu - form there I changed the DISA DN from DISA to the Hotdesking Access Number. I had a license for External Hotdesking so I created an EHD extension. From there I am able to add CPN substitution based on that extension. So external callers who are given the extension and User PIN can access this extension and place an outgoing call from our "main" number. I feel that the extension, user PIN, and COR setting should provide enough security against toll fraud since this is a temporary situation.