Profit Sharing and large coprorations

What is the name of your state? CA
I work for Clorox in California. The corporation is based in California as well. My question is if profit sharing is given to hourly employees in part of the company does the company have to give it to all hourly employees? The plant that I work in is a union plant. Most of the others are not. Other plants have been recieving profit sharing for some time. If we are entitled to it how would we go about getting retroactive profit sharing. It would be quite a large some for the number of people and the number of years involved.
Thanks for any help you can give. B

While I'm not necessarily saying it's always the best practice (sometimes, depending on the reasoning behind it, there are valid reasons for it) it is NOT illegal to offer a benefit to some employees and not all, even if all the employees in question are hourly. As long as who receives the benefit and who does not, is not decided on the basis of race, religion, national origin, gender, age, disability or pregnancy, it is legal.