Creating a wordpress plugin to enable hiding posts from cate

My site is avelim .co.il. The site is on Hebrew wordpress 3.3, using the theme Weaver 2.2.6 with many customization done by programmers. I want to be able to hide posts from category pages - for example, in [login to view URL] I don't want the 3rd post to show. I need an option to check under the post ty allow this. For this I want a custom plugin to be created. Applicant should submit a screenshot of the administration panel of the plugin. The plugin will be tested on a test site before installing it on the live site. The project should be completed within 48 hours of being awarded the project