Search Data from Company Module and Display in the Details View

Search Data from Company Module and Display in the Details View

I have created a field in the company module called "Parent Company". Now I want to display all the companies that have the parent company mentioned- in the details of the parent company. For Example: I have mentioned Company A and B both have value of the parent company as C. Now when I see the details of Company C, I want both company A & B to be displayed in a sub-section.