Joomla 2.5 - K2 plugin

I have a Joomla 2.5 membership website which uses the ‘AEC’ component ([login to view URL]) to manage subscriptions. The content of the website is stored using K2 items. I have defined three payment plans (Bronze, Silver, Gold, Platinum). Accordingly there are four user groups (Bronze, Silver, Gold, Platinum). Content gets assigned to any of these user groups. This way, only members of the respective user groups can view the content. However, at the moment this means that if a user is not logged in and not part of the respective user group, then the content is not displayed at all. It does not appear on the website at all, which makes the website look a bit “empty”. I would like the title of the K2 item and the K2 introtext to be available to all users (logged in or not). However, the full text of the K2 item (and also images, attachments of the K2 item) should only be visible to users who are logged in and belong to the respective user group. Users which belong to the “Platinum” user group shall be able to see the full text of all K2 items which belong to the Platinum, Gold, Silver, Bronze plans. Users which belong to the “Gold” user group shall be able to see the full text of all K2 items which belong to the Gold, Silver, Bronze plans (but not the Platinum plan content). Etc – Silver users can see silver & bronze content, bronze users can only see the bronze content. I will prefer bidders who can program this as an installable plugin, without K2 core hacks. If you propose to create a hack or a template override please let me know. I may still be interested. Maximum budget 100 USD. Higher bids will be dismissed as spam.