Quotation Module Line Item Function in another module


I want to add the Line Item function into one of my custom module (with modified fields). How can I get it done.

I have attached the screen shot of the function that I am referring here for better understanding.

I only want few fields and not all from the Line Item as under:

Group Name:
Description (HTML):
Couple of Relate Fields

Help in the above matter would be appreciated.

The view you see of a Quote, a Contract and a Invoice is defined by 3 different modules. I’ll recommend you to read this post to get a better insight on how it works: