Simple WordPress Plugin

SIMPLE AND FAST PROJECT. Needed in 24 hours! I need someone to make me a WordPress plugin that will do the following: 1) When I create a blog post, I want to add a short code to it. For example: [CONTINUED] 2) This plugin should take that short code and do one of two things. a) If the user IS logged in, it should do nothing when the post is loaded. b) if the user is NOT logged in, it should load the post with the following code: CONTINUED ON NEXT PAGE CONTINUED FROM PREVIOUS PAGE 3) I am not a WordPress expert, so I need this code to make it so that logged in users do not have pagination with the tag, and visitors who are not logged in never see pagination. The post simply continues as if the tag doesn't exist for them. It has to make this happen before the HTML for the page loads into the browser, and this plugin should work regardless of theme. For payment, I will create milestone for 100% and release it upon delivery of finished files.