How can I create and relate a Parent Company and a Subsidiary Company

I had the same problem with jobs (parent/child jobs) as well as customers. 
It's a little confusing at first, but I kept all customers in one table and created a relationship customer-customer. This allows for a company to be a parent or subsidiary. I hadn't looked into any of the implications of doing it this way, but maybe someone can come along and tell my why it's not a recommended option? :) 

On jobs for example - our form has a 'related jobs tab' you can either assign the parent or view child jobs from the tab.