Wordpress Functions for linking Custom Post Types

I am looking to find a method of linking 3 sets of custom post types and a template tag to display the related information. These are:

Products, Case Studies & Applications.

Products: When adding a new product custom post I want to be able to generate a list of applications (there will only be 6 but if it is dynamically generated when I add more there will be no need to change the code) as meta data and then tick whichever application is relevant.

Case Studies: When adding a new case study custom post I want to be able to generate a list of applications (there will only be 6 but if it is dynamically generated when I add more there will be no need to change the code) as meta data and then tick whichever application is relevant.

Applications: There is no need to add any links for this as the information is captured on the Product and Case Study posts.

I then need a function for each of the templates for the custom post types. These will:

Products Template function: This will generate a loop that displays the title, excerpt and thumbnail of all case studies that the currently viewed product shares an application with.

Case Studies Template function: This will generate a loop that displays the title, excerpt and thumbnail of all Products that the currently viewed case study shares an application with.

Applications Template Function: This will generate a loop that displays the title, excerpt and thumbnail of all case studies and a seperate loop for products that have the current application associated with them.

CSS Styling can be completed by me, as can the registering of the functions that generate the custom post types. What is needed is the meta boxes and the functions to generate the output html.

Any better suggestions welcomed. I can also supply a rough layout.